Imaging device and control method for imaging device

ABSTRACT

An imaging device includes an imaging section for repeatedly forming an image of a subject at a set period, while performing a bulb exposure operation, and outputting image data; an adding processing section for performing adding processing of the image data and previously output image data; an image display section for displaying the added image; and a designation section for designating to display only notification information indicating that bulb exposure is being performed, on the image display section, for a given period from commencement of the bulb exposure.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.12/268,972 (referred to as “the '972 application” and incorporatedherein by reference), filed on Nov. 11, 2008, titled “IMAGING DEVICE ANDCONTROL METHOD FOR IMAGING DEVICE,” and listing Keiji KUNISHIGE, SatoshiMIYAZAKI AND Yoji WATANABE, as the inventors, the '972 application beingbased upon and claiming benefit under 35 U.S.C. §119, to the filingdates of prior Japanese Patent Applications No. 2007-301017 filed onNov. 20, 2007, No. 2007-301018 filed on Nov. 20, 2007, No. 2007-306904filed on Nov. 28, 2007, No. 2007-306905 filed on Nov. 28, 2007, No.2007-314903 filed on Dec. 5, 2007. The entire contents of the '972application and the foregoing Japanese patent applications areincorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an imaging device and a control methodfor an imaging device, and in more detail relates to an imaging devicecapable of imaging a subject while carrying out bulb exposure or longtime exposure etc., and to a control method for an imaging device.

2. Description of the Related Art

Generally, in the case of imaging a subject such as a starry ski,fireworks or a night scene, the bulb exposure setting is often used.However, with bulb exposure appropriate exposure time (time from openingthe shutter to closing the shutter) varies depending on the photographedimage and ambient conditions, and it was necessary for the photographerto determine exposure time on their own without looking at a completedimage. Therefore, if that determination was wrong, there was a problemof over or under exposure.

At the time of bulb exposure therefore, if a photographed image can beobserved according to exposure, it will be possible to observe exposurelevels in real time, and determining exposure time will be simplified.For example, Unexamined Japanese patent application No. 2005-117395(laid-open Apr. 28, 2005) discloses am imaging device for acquiringimage signals from an image sensor at specified time intervals (forexample, 1/10th of a second) during an exposure operation, anddisplaying a sequentially summed image on a liquid crystal monitor.

SUMMARY OF THE INVENTION

The present invention has as its object to provide an imaging devicewith which a photographer can recognize that an exposure operation isprogressing, in a long time exposure such as bulb exposure, and acontrol method for an imaging device.

According to the present invention, there is provided an imaging device,comprising: an imaging section, including an image sensor for imaging asubject, for generating image data based on output signals of the imagesensor; a control section for causing repeated operation of the imagingsection in accordance with a single release operation; an addingprocessing section for sequentially adding image data repeatedly outputfrom the imaging section and generating added mage data; an imagedisplay section for displaying the added image data, and a settingsection for setting a repeat period for the imaging section andinstructing to the control section.

There is also provided an imaging device of the present invention,comprising: an imaging section for repeatedly forming an image of asubject at a set period, while performing a bulb exposure operation, andoutputting image data; an adding processing section for performingadding processing of the image data and previously output image data; anadded image storage section for respectively independently storing aplurality of added images that have been added by the adding processingsection; and a display section for displaying, in a list, the pluralityof added images that have been stored in the added image storage sectionafter completion of the bulb exposure operation.

Further, a control method for an imaging device of the present inventioncomprises: repeatedly forming an image of a subject, generating imagedata based on the formed subject image, sequentially adding image data,and repeatedly displaying added image data.

Further, a control method for an imaging device of the present inventioncomprises: repeatedly forming an image of a subject, generating imagedata based on the formed subject image, sequentially adding image data,successively storing added image data, and performing list display ofthe stored image data, after exposure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an external perspective drawing looking at a digital singlelens reflex camera of a first embodiment of the present invention from arear surface.

FIG. 2 is a block diagram showing the overall structure of electricalsystems of a digital single lens reflex camera relating to a firstembodiment of the present invention.

FIG. 3 is a block diagram showing in abstract form the structurerelating to image forming and display in bulb mode etc., in a digitalsingle lens reflex camera of the first embodiment of the presentinvention.

FIG. 4 is a flowchart showing a power on reset operation of the firstembodiment of the present invention.

FIG. 5 is a flowchart showing a cycle time input operation of the firstembodiment of the present invention.

FIG. 6 is a flowchart showing a shooting operation of the firstembodiment of the present invention.

FIG. 7 is a flowchart showing an exposure operation of the firstembodiment of the present invention.

FIG. 8 shows respective regions of an image sensor of a digital singlelens reflex camera relating to a first embodiment of the presentinvention.

FIG. 9 is a graph showing a relationship between temperature, relatingto dark current, and integration level in an image sensor of a digitalsingle lens reflex camera of the first embodiment of the presentinvention.

FIG. 10 shows exposure information display of a digital single lensreflex camera relating to a first embodiment of the present invention.

FIG. 11 shows update display for a digital single lens reflex camera ofthe first embodiment of the invention, with FIG. 11( a) to FIG. 11( e)showing display of respectively different cycle times.

FIG. 12 shows display of bulb mode exposure time for the firstembodiment of the invention, with FIG. 12( a) to FIG. 12( g) showingchange with lapse of cycle time.

FIG. 13 is a flowchart showing a power-on reset operation of a secondembodiment of the present invention.

FIG. 14 is a flowchart showing an exposure operation of the secondembodiment of the present invention.

FIG. 15 is a flowchart showing resetting of cycle time in a secondembodiment of the present invention.

FIG. 16 is a block diagram showing the overall structure of electricalsystems of a digital single lens reflex camera relating to a thirdembodiment of the present invention.

FIG. 17 is a block diagram showing in abstract form the structurerelating to image forming and display in bulb mode etc., in a digitalsingle lens reflex camera of the third embodiment of the presentinvention.

FIG. 18 is a flowchart showing a cycle time input operation of the thirdembodiment of the present invention.

FIG. 19 is a flowchart showing an exposure operation of the thirdembodiment of the present invention.

FIG. 20 shows display of bulb mode exposure time for the thirdembodiment of the invention, with FIG. 20( a) to FIG. 20( g) showingchange with lapse of cycle time.

FIG. 21 is a flowchart showing an exposure operation of a fourthembodiment of the present invention.

FIG. 22 shows display of bulb mode exposure time for the fourthembodiment of the invention, with FIG. 22( a) to FIG. 22( g) showingchange with lapse of cycle time.

FIG. 23 is an external perspective drawing looking at a digital singlelens reflex camera of a fifth embodiment of the present invention from arear surface.

FIG. 24 is a block diagram showing the overall structure of electricalsystems of a digital single lens reflex camera relating to the fifthembodiment of the present invention.

FIG. 25 is a block diagram showing in abstract form the structurerelating to image forming and display in bulb mode etc., in a digitalsingle lens reflex camera of the fifth embodiment of the presentinvention.

FIG. 26 is a flowchart showing an exposure operation of a fifthembodiment of the present invention.

FIG. 27 shows display of bulb mode exposure time for the fifthembodiment of the invention, with FIG. 27( a) to FIG. 27( g) showingchange with lapse of cycle time.

FIG. 28 is a flowchart showing an exposure operation of a sixthembodiment of the present invention.

FIG. 29 is a flowchart showing an exposure operation of a seventhembodiment of the present invention.

FIG. 30 is a flowchart showing an exposure operation of an eighthembodiment of the present invention.

FIG. 31 is a flowchart showing an exposure operation of the eighthembodiment of the present invention.

FIG. 32 is a block diagram showing the overall structure of electricalsystems of a digital single lens reflex camera relating to a ninthembodiment of the present invention.

FIG. 33 is a block diagram showing in abstract form the structurerelating to image forming and display in bulb mode etc., in a digitalsingle lens reflex camera of the ninth embodiment of the presentinvention.

FIG. 34 is a flowchart showing an exposure operation of the ninthembodiment of the present invention.

FIG. 35 shows display of bulb mode exposure time for the ninthembodiment of the invention, with FIG. 35( a) to FIG. 35( g) showingchange with lapse of cycle time.

FIG. 36 is a block diagram showing in abstract form the structurerelating to image forming and display in bulb mode etc., in a digitalsingle lens reflex camera of a tenth embodiment of the presentinvention.

FIG. 37 is a flowchart showing a shooting operation of the tenthembodiment of the present invention.

FIG. 38 is a flowchart showing an exposure operation of the tenthembodiment of the present invention.

FIG. 39 shows display of bulb mode exposure time for the tenthembodiment of the invention, with FIG. 39( a) to FIG. 39( g) showingchange with lapse of cycle time.

FIG. 40A and FIG. 40B show list display of all added images at the timeof completion of bulb mode exposure with the tenth embodiment of thepresent invention, with FIG. 10A being a list display immediately afterexposure completion, and FIG. 40B being list display for a selectedtime.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the following, preferred embodiments using a digital single lensreflex adopting the present invention will be described using thedrawings. FIG. 1 is an external perspective drawing of a digital singlelens reflex camera relating to a first embodiment of the presentinvention seen from a rear surface.

This digital single lens reflex camera comprises a camera body 200 andan interchangeable lens 100. A release button 21, exposure mode dial 22,information setting dial 24, and strobe 50 etc. are arranged on theupper surface of the camera body 200. The release button 21 has a firstrelease switch that turns on if the photographer presses the button downhalfway, and a second release switch that is turned on when the buttonis pressed down fully.

By turning this first release switch (hereafter called 1R) on, thecamera carries out exposure preparation operations such as focal pointdetection, focusing of the photographing lens, and metering for thesubject brightness, and as a result of turning the second switch(hereafter called 2R) on, the camera executes a shooting operation toacquire image data for a subject image based on output of the imagesensor 221 (refer to FIG. 2).

The exposure mode dial 22 is an operation member constructed capable ofrotation, and by aligning a pictorial display or symbol representing anexposure mode provided on the exposure mode dial 22 with an index, it ispossible to select respective exposure modes, such as program exposuremode (P), aperture priority exposure mode (A), shutter speed priorityexposure mode (S), manual exposure mode (M), and bulb mode (B).

An information setting dial 24 is an operation member constructedcapable of rotation, and it is possible to select desired setting valuesand modes etc. in an information display screen or the like byrotational operation of the information setting dial 24. If shutterspeed priority exposure mode or manual exposure mode are selected usingthe exposure mode dial 22, it is possible to set a shutter speed usingthe information setting dial 24, and it is also possible to set to along time of 30 seconds or more. It is also possible to carry outsetting of a cycle time for image display during exposure at the time ofbulb exposure or long exposure time.

The strobe 50 is a pop-up type supplemental lighting unit, and byoperating an operating button, not shown, the strobe 50 pops up and iscapable of irradiating light to a subject.

A rear surface liquid crystal monitor 26, continuous/single shot button22, AE lock button 28, a cross-shaped button for up 30U, a cross-shapedbutton for down 30D, a cross-shaped button for right 30R, a cross-shapedbutton for left 30L, (if these buttons 30U, 30D, 30R and 30L arereferred to collectively, it will be called a cross-shaped button 30),an OK button 31, a live view display button 33, an enlarge button 34, amenu button 37 and a playback button 38 are arranged on the rear surfaceof the camera body 200.

The rear surface liquid crystal monitor 26 is a display unit forcarrying out live view display, playback display of a subject imagesthat have already been taken, and display of exposure information andmenus. Also, at the time of bulb exposure or long time exposure etc.image display is carried out during the exposure operation based onimage signals acquired by the image sensor 221. The monitor is notlimited to a liquid crystal display as long as it is possible to performthese display operation.

The continuous/single shot button 27 is an operation member switchingbetween continuous shooting mode where pictures are taken continuouslywhile the release button 21 is fully pressed down, and, single shot modewhere a single picture is taken if the release button 21 is pressed downfully. The AE lock button 28 is an operation member for fixing a meteredvalue. After brightness of an exposed image has been metered, if this AElock button 28 is operated the metered value is maintained even if thecomposition is changed, and it is possible to take a picture withoutaltering the exposure level.

The cross-shaped button 30 is an operation member for instructingmovement of a cursor in two dimensional directions, the X direction andY direction, on the rear surface liquid crystal display monitor 26, andis also used in selection commands for a subject image, when performingplayback display of subject images that have been stored in the storagemedium 277 etc. Besides providing four buttons for up, down, left andright, it is also possible to replace with an operating member capableof operation in two dimensional directions, such as a touch switch

The OK button 31 is an operation member for confirming various itemsselected by the cross-shaped button 30 and the control dial 24 etc.

The live view display button 33 is an operating button for switching tolive view display from a display screen for information display etch, orswitching from live view display to a display screen for informationdisplay etc. Live view display is a mode that displays a subject imagefor viewing on the rear surface liquid crystal monitor 26 based onoutput of the image sensor 221 for subject image storage, andinformation display is a mode for displaying exposure information of thedigital single lens reflex camera on the rear surface liquid crystalmonitor 26 for display setting.

The enlargement button 34 is an operation member for enlarging displayof part of a subject image on the rear surface liquid crystal monitor26, and it is possible to change the enlargement position by operationof the above-described cross-shaped button 30.

The menu button 37 is an operation member for switching to menu mode inorder to set various modes of this digital single lens reflex camera,and if menu mode is selected by operation of this button 37 a menuscreen is displayed on the rear surface liquid crystal monitor 26. Themenu screen is comprised of a multiple hierarchical structure, andvarious items are selected using the cross-shaped button 30 andselection is determined by operating the OK button 31.

The playback button 38 is an operation button for instructing display ofsubject images, that have been stored after being taken, on the rearsurface liquid crystal monitor 26. Image data of subjects stored in acompressed mode such as JPEG, for example, in SDRAM (Synchronous DynamicRandom Access Memory) 267 and a storage medium 277, that will bedescribed later, is expanded and displayed.

A storage medium housing cover 40 is attached to the side surface of thecamera body 200. If this storage medium cover 40 is opened, a slot forfitting the storage medium 277 is provided inside, and the storagemedium 277 can be loaded into or removed from the camera body 200.

Next, the overall structure principally involved in the electricalsystems of the digital single lens reflex camera will be described usingFIG. 2. With this embodiment, the interchangeable lens 100 and thecamera body 200 are constructed as separate bodies, electricallyconnected by means of a communication contact 300, but it is alsopossible to integrally construct the interchangeable lens 100 and thecamera body 200. A circuit block for the built-in strobe 50 is omittedfrom FIG. 2.

A photographing optical system 101 for focusing and focal lengthadjustment, and an aperture 103 for adjusting aperture, are arrangedinside the interchangeable lens 100. The photographing optical systemlens 101 is driven by a lens drive mechanism 107, while the aperture 103is driven by the aperture drive mechanism 109.

The lens drive mechanism 107, and the aperture drive mechanism 109 arerespectively connected to a lens CPU 111, and this lens CPU 111 isconnected to a communication circuit 273 of the camera body 200 by meansof the communication contact 300. The lens CPU 111 performs controlinside of the interchangeable lens 100, controls the lens drivemechanism 107 to perform focusing and zoom operations, and controls anaperture value by controlling the aperture drive mechanism 109.

Also, the lens CPU 111 transmits lens specific information such asmaximum aperture value and focal length information of theinterchangeable lens 100, and focal length and focus positioninformation detected by the optical system positional detectionmechanism (not shown in the drawing) to the camera body 200.

Inside the camera body 200, a rotatable moving mirror 201 is providedmoving between a position inclined by 45 degrees with respect to thelens optical axis for reflecting a subject image to a viewfinder opticalsystem (lowered position, subject image viewing position), and a raisedup position for guiding the subject image to the image sensor 221(raised position, retracted position).

A focusing screen 205 for image forming the subject image is arrangedabove the movable mirror 201, and a pentaprism 207 for lateral inversionof the subject image is arranged above this focusing screen 205.

An ocular lens (not shown) for viewing the subject image is arranged atan outgoing side of this pentaprism 207 (the right side in FIG. 2), anda photosensor 211 is arranged next to the ocular lens at a position thatdoes not obstruct viewing of the subject image. This photosensor 211 isconnected to a photometry processing circuit 241, and output of thephotosensor 211 is subjected to processing such as amplificationprocessing and analog-digital conversion by this photometry processingcircuit 241.

A half mirror is constructed close to the middle of the movable mirror201, and a sub-mirror 203 for reflecting the subject image that haspassed through the half mirror to a lower section of the camera body 200is provided on a rear surface of the movable mirror 201.

This sub mirror 203 is capable of rotation with respect to the movablemirror 201, and when the movable mirror 201 is raised up (position shownby dotted lines in FIG. 2) the sub mirror 203 rotates to a positioncovering the half mirror part, while when the movable mirror 201 is in asubject image viewing position (lowered position) the sub-mirror 203 isat a position opened with respect to the movable mirror 201, as shown inthe drawing.

This movable mirror 201 is driven by a movable mirror drive mechanism239. Also, a focal point detection sensor 243 is arranged below thesub-mirror 203, and output of this focal point detection sensor 243 isconnected to a focal point detection processing circuit 245. The focalpoint detection sensor 243 measure defocus amount for a subject imageformed using the photographing optical system 101, and is constructed ofa well-known phase difference AF optical system for separatingperipheral light of the photographing optical system 101 into twoluminous fluxes, and a pair of sensors.

A focal plane type shutter 213 for exposure time control is arrangedbehind the movable mirror 201, and drive control for this shutter 213 isperformed by a shutter drive mechanism 237. An image sensor 221 isarranged behind the shutter 213, and a subject image formed by thephotographing optical system 101 is photoelectrically converted intoelectrical signals. It goes without saying that it is possible to useCCD (Charge Coupled Devices), or a two-dimensional fixed imaging elementsuch as CMOS (Complementary Metal Oxide Semiconductor) as the imagesensor 211.

An infrared cut filter/low pass filter 217, which is an optical filterfor removing an infrared component and a high frequency component fromsubject light flux, is arranged between the shutter 213 and the imagesensor 221. A temperature measurement circuit 231 is also arranged closeto the image sensor 221. This temperature measurement circuit 231measures ambient temperature close to the image sensor 221 usingtemperature dependence of forward current of a diode, and outputs atemperature signal according to the ambient temperature.

The image sensor 221 is connected to an image sensor drive circuit 223,and readout of image signals from the image sensor 221 etc. is performedby this image sensor drive circuit 223. The image sensor drive circuit223 is connected to an ADC (analogue to Digital Converter) 225 forcarrying out analogue to digital conversion of an image signal.

Output of the ADC 225 is connected to a dark current elimination circuit227. The dark current elimination circuit 227 is a circuit for removingdark current generated by the image sensor 221, and corrects image datathat represents a subject using dark current generated in a shieldedregion of a peripheral section of the image sensor 221.

The dark current elimination circuit 227 is connected to data bus 252inside an ASIC (Application Specific Integrated Circuit) 250. A sequencecontroller (hereafter referred to as a body CPU) 251, image processingcircuit 257, compression and expansion circuit 259, video signal outputcircuit 261, SDRAM control circuit 265, input/output circuit 271,communication circuit 273, storage medium control circuit 275, flashmemory control circuit 279 and switch sensing circuit 283 are connectedto this data bus 252.

The body CPU 251 that is connected to the data bus 252 controlsoperation of this digital single lens reflex camera. The imageprocessing circuit 257 is connected to the data bus 252 and carries outvarious image processing such as digital amplification of digital imagedata (digital gain adjustment processing), color correction, gamma (γ)correction, contrast correction and image generation for live viewdisplay etc.

Also, the compression and expansion circuit 259 is a circuit forcompressing image data stored in the SDRAM 267 using a compressionsystem such as JPEG, TIFF etc. and expanding compressed image data. Theimage compression is not limited to JPEG and TIFF, and it is alsopossible to apply other compression systems.

The video signal output circuit 261 is connected to the rear surfaceliquid crystal monitor 26 via a liquid crystal monitor drive circuit263. The video signal output section 261 converts image data stored inthe SDRAM 267 or the storage medium 277 into video signals for displayon the rear surface liquid crystal monitor 26. The rear surface liquidcrystal monitor 26 is arranged on the rear surface of the camera body200 as shown in FIG. 1, but as long as it is in a position that can beseen by the photographer it is not limited to the rear surface, and alsois not limited to liquid crystal and can be another display device.

The SDRAM 267 is connected via the SDRAM control circuit 265 to the databus 252, and this SDRAM 267 acts as a buffer memory for temporarilystoring image data that has been subjected to image processing by theimage processing circuit 257 or image data that has been compressed bythe compression and expansion circuit 259.

The input/output circuit 271 connected to the above described imagesensor drive circuit 223, temperature measurement circuit 231, shutterdrive mechanism 237, movable mirror drive mechanism 239, photometryprocessing circuit 241, and focal point detection processing circuit 245controls input and output of data to various circuits, such as the bodyCPU 251 via the data bus 252.

The communication circuit 273 that is connected to the lens CPU 111 viathe communication contact 300 is also connected to the data bus 252, andcarries out data exchange with the body CPU 251 etc. and communicationfor control commands. The storage medium control circuit 275 connectedto the data bus 252 is connected to the storage medium 277, and performscontrol of storing image data etc. to this storage medium 277 andreading out of image data etc.

The storage medium 277 is constructed so that any rewritable storagemedium, such as xD picture card, (registered trademark), Compact Flash(registered trademark), SD memory Card (registered trademark) or memorystick (registered trademark) can be fitted, and is removably insertedinto the camera body 200. Besides, it is also possible to have aconfiguration where it is possible to connect to a hard disc via acommunication connection point.

The flash memory control circuit 279 is connected to a flash memory 281,and this flash memory 281 stores programs for controlling operation ofthe digital single lens reflex camera, and the body CPU 251 performscontrol of the digital single lens reflex camera in accordance with theprograms stored in the flash memory 281. Incidentally, the flash memory281 is an electrically rewritable non-volatile memory.

Various switches 285, including a 1R switch for detecting a first stroke(half press) of the release button 21 and a 2R switch for detecting asecond stroke (full press) of the release button 21, a power switch, amenu switch linked to the menu button 37, a dial switch linked to theexposure mode dial 22, a dial switch linked to the information settingdial 24, and various switches liked to other operating members, isconnected to the data bus 252 via a switch detection circuit 283.

Next, the structure relating to image display during exposure, in bulbexposure etc., will be described using FIG. 3. The control section 297is constructed of a body CPU 251 for controlling the overall digitalsingle lens reflex camera. When using bulb exposure mode, the settingsection 298 automatically sets a cycle time for display in order toconfirm progress of the exposure (exposure level) based on manualoperation using the information setting dial 24 or exposure informationetc.

The imaging section 291 includes the image sensor 221, image sensordrive circuit 223, ADC circuit 225 and dark current elimination circuit227, and outputs image data based on image signals. Output of theimaging section 291 is connected to the adding processing section 294.

The adding processing section 294 performs adding processing of imagesacquired every predetermined time during bulb exposure or long timeexposure, and generates added mage data. A temporary storage section 293is constructed using a temporary storage device such as SDRAM 267, andtemporarily stores image data that has been added in the addingprocessing section 294, supplies already stored added image data inaccordance with control commands from the control section 297 to theadding processing section 294, and once more stores newly added imagedata.

The adding processing section 294 is constructed using a body CPU 251and an image processing circuit 257 etc., and in accordance with controlcommands from the control section 297 carries out processing to addadded image data that is already stored in the temporary storage section293 with newest image data.

An added image storage section 295 is constructed using a storage mediumsuch as the previously described storage medium 277, and reads out themost recent added image data that has been added in the addingprocessing section 294 in accordance with control commands from thecontrol section 297, and stores this data.

The image display section 296 is made up of a rear surface liquidcrystal monitor 26 and a liquid crystal monitor drive circuit 263 etc.,and, every time added image data that has been added by the addingprocessing section 294 is updated and stored in the temporary storagesection 293, reads out the data from the temporary storage section 293in accordance with control commands from the control section 297 todisplay the added image data.

With this type of structure, first an operator sets a cycle time byoperating the setting section 298. The control section 297 performscontrol so that image data that has been acquired by the imaging section291 is sequentially added by the adding processing section 294 every setcycle time, and this added image is displayed on the image displaysection 296.

As shown in FIG. 12, this added image is a gradual cumulative additionof image data, and initially is a dark image, as shown in FIG. 12( a),but if the image gradually changes to a brighter image, images arerepeatedly cumulatively added a number of times and it will become animage that seems over exposed, as shown in FIG. 12( g).

Next, detailed operation of the digital single lens reflex camera of afirst embodiment of the present invention will be described using theflowcharts shown in FIG. 4 to FIG. 7.

FIG. 4 shows a power on reset operation performed by the body CPU 251 atthe camera body 200 side. If a battery is fitted into the camera body200, this flow of operations starts, and it is determined whether or notthe power switch of the camera body 200 is on (#1).

When the result of determination is that the power switch is off, asleep state, which is a low power consumption state, is entered (#3). Inthis sleep state, interrupt processing is carried out only when thepower switch is turned on, and processing for power switch on is carriedout in steps #5 and after. Until the power switch is turned on,operations other than power switch interrupt processing are suspended,and consumption of the power supply battery is prevented. In the eventthat the power switch was on in step #1, or the sleep state of step #3is left, supply of power commences (#5).

Next, if there is information such as exposure mode set by the exposuremode dial 22, ISO speed set by the information setting dial 24, orshutter speed or aperture value set manually, reading in of theseexposure conditions and lens information is carried out (#7).

Reading of lens information in step #7 is the reading of lens specificinformation, such as maximum aperture of the interchangeable lens 100,and focal length information, from the lens CPU 111 by means of thecommunication circuit 273. In this step, in the event that bulb modeexposure has been set, or a long time has been set as the shutter speed,these items of information are read.

It is next determined whether or not bulb mode has been set (#9). Fromthe fact that the exposure mode is read in step #7, it is determinedwhether or not bulb mode has been set as the read exposure mode.

If the result of determination in step #7 is that bulb mode has not beenset, metering and exposure value calculation is carried out (#11). Inthis step, subject brightness is then measured by the photosensor 211,exposure amount is calculated, and exposure control values such asshutter speed and aperture value are calculated in accordance withexposure mode and exposure conditions, using this exposure value.

If the result of determination in step #9 is that bulb mode has beenset, input of cycle time (cycle for repeatedly outputting image data) iscarried out (#31). Input of this cycle time will be described laterusing FIG. 5. If input of cycle time is completed, processing advancesto step #13. In the case of bulb mode, since opening and closing of theshutter 213 is carried out by user operation and is not related tometering, the metering and exposure value calculation of step #11 arenot executed.

Next, the exposure information is displayed on the rear surface liquidcrystal monitor 26 (#13). As exposure information, there are exposuremode and exposure conditions read in step #7 and exposure control valuesfor shutter speed and aperture value calculated in #11. In the eventthat bulb mode has been set as the exposure mode, then as shown in FIG.10, a bulb mode display 301 and cycle time display 302 are displayed onthe rear surface liquid crystal monitor 26 together with other exposureinformation.

If display of exposure information is carried out, it is next determinedwhether or not a playback switch linked to the playback button 38 is on(#17). Playback mode is a mode for reading out image data stored in thestorage medium 277 and displaying them on the rear surface liquidcrystal monitor 26, when the playback button 38 has been operated. Ifthe result of determination is that the playback switch is on, aplayback operation is executed (#33).

If the result of determination in step #17 is that the playback switchis not on, it is determined whether or not the menu switch that links tothe menu button 37 is on (#19). In this step, it is determined whetheror not the menu button 37 has been operated and the menu mode has beenset. If the result of determination is that the menu switch is on, menudisplay is performed on the rear surface liquid crystal monitor 26, anda menu setting operation is carried out (#35). Various settingoperations such as AF mode, white balance, ISO speed setting, drive modesetting etc. can be carried out by the menu setting operation.

If the determination result in step #19 is that the menu switch is noton, it is next determined whether or not the release button 21 has beenpressed down halfway, that is, whether or not the 1R switch is on. Ifthe result of determination is that the 1R switch is on, a shootingoperation sub-routine is executed to carry out exposure preparation andshooting (#37). This sub-routine will be described in detail later usingFIG. 6.

If the result of determination in step #21 is that the 1R switch is noton, then similarly to step #1 it is determined whether or not the powerswitch is on (#23). If the result of determination is that the powerswitch is on, processing returns to step #7 and the operations describedabove are repeated. On the other hand, if the power switch is not on,supply of power is stopped (#25), and processing returns to step #3where the previously described sleep state is entered.

Next, the input operation for cycle time of step #31 will be describedusing FIG. 5. If this subroutine is entered, ambient temperature closeto the image sensor 221 that has been measured by the temperaturemeasurement circuit 231 is first detected (#41). If the ambienttemperature is obtained, determination of an upper limit value for cycletime is carried out based on this ambient temperature (#43).

As is shown conceptually in FIG. 8, photodiodes (pixels) are arrayed intwo dimensional directions on the image sensor 221. In FIG. 8, eachsquare represents a pixel. A majority of the pixels of the image sensor221 are the effective pixel region 311, with the right side constitutinga horizontally shielded pixel region 312 and the lower side constitutinga vertically shielded pixel region 313. Image data is generated based onpixel signals output from pixels belonging to the effective pixel region311, while dark current data is generated based on pixel signals outputfrom pixels belonging to the horizontally shielded pixel region 312 andthe vertically shielded pixel region 313.

As shown in FIG. 9, this dark current has a temperature dependentcharacteristic, and as the temperature close to the image sensor 221become hot, the dark current (integrated value) also rapidly becomeslarge as time passes. Dark current is superimposed on the pixel signalsof the subject image output from the image sensor 221 that have beenphotoelectrically converted, and if exposure time (integration time)becomes long the dark current can no longer be ignored. Dark currentoutput from the horizontally shielded pixel region 312 and thevertically shielded pixel region 313 is also assumed to be generated inthe effective pixel region 311, and in the dark current eliminationcircuit 227 dark current correction is carried out by deducting darkcurrent data from image data based on the pixel signals.

The dark current quickly reaches saturation level as the temperaturebecomes high. If the dark current reaches saturation level, it will notbe possible to correctly perform dark current elimination. In thisembodiment therefore, in the event that an exposure operation is carriedout over a long time, such as bulb mode, pixel signals are read from theimage sensor 221 before the dark current reaches saturation level.Specifically, taking into consideration the dark current characteristic,the upper limit value for cycle time is controlled based on ambienttemperature measured by the temperature measuring circuit 231 so thatdark current does not saturate (#43). Specifically, a table for ambienttemperature and upper limit value is stored, and determination is madeby referring to this table.

Next, in order to input cycle time, it is determined whether or not theinformation setting dial 24 has been operated (#45). If the result ofdetermination is that the information setting dial 24 has not beenoperated, the original routine is returned to. On the other hand, if theinformation setting dial 24 has been operated the switch detectioncircuit 283 detects direction of rotation of the dial (#47).

It is next determined whether or not the detection direction of rotationis a direction that causes a reduction in cycle time (#49). If theresult of determination is that the rotation direction causes areduction in cycle time, it is determined whether or not the previouscycle time has reached a lower limit value (#51). The lower limit valueshould be set appropriately, but can be, for example, about 0.1 seconds.If the result of determination is that the lower limit value has notbeen reached, the cycle time is successively shortened in predeterminedsteps from the currently set state (#53).

As shown in FIG. 10, the cycle time is displayed as a cycle time display302 within exposure information on the rear surface liquid crystalmonitor 26. Every time there is a rotation operation using theinformation setting dial 24 in a direction to shorten the cycle time,for example, if the currently set state is an initial value of 30second, there is a gradual reduction in predetermined steps from FIG.11( c) towards the lower limit value of FIG. 11( a). The predeterminedstep should be appropriately set taking into consideration ease of use.Once cycle time shortening is finished, the original routine is returnedto.

If the result of determination in step #49 is that the rotationdirection is not such as to reduce cycle time, then it is determinedwhether or not the previous cycle time has reached the upper limit valuedetermined in step #43 (#55). If the result of determination is that theupper limit value has not been reached, the cycle time is successivelyextended in predetermined steps (#57). Every time there is a rotationoperation using the information setting dial 24 in a direction toincrease the cycle time, there is a gradual increase, in predeterminedsteps, from the current state towards the upper limit value of FIG. 11(e). The cycle time intervals of FIG. 11( a) to (e) are only one example,and can be appropriately changed.

Next, the shooting operation of step #37 will be described using FIG. 6.This subroutine is started if the 1R switch is turned on, and the firstthing to happen is that exposure information being displayed on the rearsurface liquid crystal monitor 26 is turned off (#61). Next, a phasedifference AF subroutine is executed (#63). In this subroutine, defocusdirection and defocus amount of the photographing system 101 aredetected using well-known phase difference AF, drive control for theoptical system drive mechanism 107 is carried out based on this defocusdirection and defocus amount, and focusing of the photographing opticalsystem 101 is carried out.

If phase difference AF is completed, then similarly to step #9 it isdetermined whether or not bulb mode has been set (#65). If the result ofdetermination is that bulb mode has not been set, metering and exposurevalue calculation are carried out, and exposure control values such asshutter speed and aperture value are obtained (#67).

On the other hand, if the result of determination in step #65 is thatbulb mode has been set, step #67 is skipped and processing advances tostep #69. In the case of bulb mode, as described previously, the timefor opening and closing the shutter 213 is determined by thephotographer, and metering and exposure value calculation are notrequired.

Next it is determined whether or not the shutter button 21 has beenpressed down fully, that is, if the 2R switch is on (#69). If the resultof determination is that the 2R switch is not on, it is then determinedwhether or not the 1R switch is on (#87). If the result of determinationis that the 1R switch is not on, the shooting operation is terminatedand the original routine is returned to. On the other hand, if theresult of determination is that the 1R switch is on, step #69 isreturned to, and a standby state is entered where the states of the 1Rswitch and the 2R switch are alternately detected.

If the result of determination in step #69 is that the 2R switch is on,processing transfers to a step for performing exposure. First aretraction operation for the movable mirror 201 (moving to the raisedposition) is carried out (#71). As a result, subject light flux isguided to the image sensor 221 by the photographing optical system 101.Next, a stopping down operation is instructed to the lens CPU 111 and astopping down operation for the aperture 103 is carried out (#73).

As a result, it is possible to prepare entry to the normal exposureoperation or the bulb exposure operation, and so an exposure operationis started (#75). Exposure is the starting of travel of the frontcurtain of the shutter 213, together with charge accumulation of theimage sensor 221. If a time corresponding to the shutter speed acquiredin step #67 or a shutter speed that was manually set by the photographerhas elapsed, or if bulb exposure completion has been instructed by thephotographer, travel of the rear curtain of the shutter 213 starts, andcharge accumulation of the image sensor 221 is terminated.

At the time of this exposure operation, if bulb mode has been set, thenwhile the release button 21 is being pressed down completely the shutter213 is open, and at this time image data is repeatedly acquired usingthe image sensor 221 at intervals of the cycle time, and an image isdisplayed on the rear surface liquid crystal monitor 26 while beingupdated, based on this image data. This exposure will be described indetail later using FIG. 7.

If the exposure operation is completed, an instruction to open up theaperture 103 is output to the CPU 111, and the aperture 103 is opened up(#77). Then, the movable mirror 201 is restored to the lowered position(#79), and image processing is carried out for a normal image that isread out from the image sensor 221 and temporarily stored in the SDRAM267 or added image data (#81). Image data that has been image processedis stored in the storage medium 277 (#83), and display of the image thatwas being displayed on the rear surface liquid crustal monitor isstopped (#85). Once image display 26 is stopped, the original routine isreturned to.

Next, the exposure operation of step #75 will be described using FIG. 7.If this subroutine is entered, first, similarly to step #9, it isdetermined whether or not bulb mode has been set (#101). If the resultof determination is that bulb mode has not been set, normal exposuremode, such as program exposure mode, is executed.

As the normal exposure mode, first a timer for exposure time timing isstarted (#103), and together with opening of the shutter 213 exposure tothe image sensor 221 is commenced (#105). That is, photoelectricconversion of a subject image formed on the image sensor 221 is carriedout, and accumulation of signal charge is commenced.

If exposure is started, it is next determined whether or not an exposuretime (set time) corresponding to a shutter speed calculated in step #67or set manually has elapsed (#107). If the result of determination isthat the exposure time has elapsed, imaging on the image sensor 221 isstopped together with closing of the shutter 213 (#109).

Next, reading of image signals from the image sensor 221 is carried out(#111), and the read out image signals are temporarily stored in theSDRAM 267 (#113). Display of an exposed image is carried out on the rearsurface liquid crystal monitor 26 based on the temporarily stored imagesignals (#115).

If the result of determination in step #101 is that bulb mode has beenset, first of all data of the added image storage region (not shown)allocated inside the temporary storage section 293 is cleared (#120), atimer for display cycle time timing is started (#121), and similarly tostep #105 imaging is commenced with the opening of the shutter 213(#123). Next, it is determined whether or not the timer for cycle timetiming has reached the cycle time set in step #31 (#125).

If the result of determination in step #125 is that the cycle time hasnot elapsed, it is determined whether or not the full pressing of therelease button 21 has been released, that is, whether or not the 2Rswitch is off (#151). In the event that the 2R switch is on and thecycle time has not elapsed, a standby state is entered where thedeterminations at steps #125 and #151 are alternately executed.

If the result of determination in step #125 is that the cycle time haselapsed, image forming of the image sensor 221 is stopped with theshutter 213 still open, and reading of image signals is carried out(#127, #129). Image data resulting from digitalization of the read imagesignals is temporarily held in a newest image saving region inside thestorage region of the temporary storage section 293 (#131). This holdingof the data is temporary saving for the adding processing of read imagedata that will be executed later.

Next, the timer for cycle time timing is restarted (#133), and imagingon the image sensor 221 is commenced (#135). Following on, previouslyadded image data stored in the added image storage region of thetemporary storage section 293, and the above described newest imagedata, are added by the adding processing section 294. The result ofadding processing is again stored in the added image storage region ofthe temporary storage section 293 (#137) and this stored added image isdisplayed on the rear surface liquid crystal monitor 26 (#139). If theadded image is displayed, step #125 is returned to, and the previouslydescribed steps are executed.

If the photographer looking at the displayed image decides that theexposure level has reached an intended level, and full pressing of therelease button 21 is released, that is, if the 2R switch is turned off,in accordance with the determination of step #151 processing advancesfrom step #151 to step #153, and a transfer is made to processing forcompletion of the exposure operation.

That is, similarly to steps #109, #111 and #113, imaging stops togetherwith closing of the shutter 213, image date is read out, and temporaryholding of image data is carried out (#153, #155, #157). Then, similarlyto steps #137 to #139, an added mage resulting from addition processingis acquired, and this added image is displayed after being stored (#159,#160, #161). Once the added image is displayed, the original routine isreturned to.

In this way, every time the cycle time set in step #31 elapses (Y instep #125) imaging by the image sensor 221 is stopped, image signals areread in, added to already added image data stored in the temporarystorage section and, as shown in FIG. 12, displayed on the rear surfaceliquid crystal monitor 26. At the point in time when the cycle timeinitially elapses, since cycle time is short a completely dark imageresults, and the image is gradually made brighter by adding image dataeach time the cycle time elapses. The photographer can determine whetheror not an intended brightness has been reached by observing the rearsurface liquid crystal monitor 26.

With this embodiment, if bulb mode has been set the imaging operation isrepeated at intervals of the cycle time during the exposure operation,and image data is stored in the temporary storage section 293 every timethe imaging operation is carried out, and an added image resulting fromadding the stored image data is displayed on the rear surface liquidcrystal monitor 26. This cycle time can be manually set using thesetting section 298, and can be appropriately changed. It is thereforepossible to carry out display updating at an effective timing accordingto the exposure conditions of the photographer's intentions.

Also in this embodiment, the cycle time is controlled to a set value sothat an upper limit value and a lower limit value are not exceeded. As aresult, it is possible to prevent use that exceeds the performance ofthe image sensor 221. Further, in this embodiment, the upper limit ofthe cycle time is varied in accordance with a dark currentcharacteristic. This means that it is possible to carry out correctionof image data in accordance with the dark current, and it is possible togive an image with less noise.

Next, a second embodiment of the present invention will be describedusing FIG. 13 to FIG. 15. With the first embodiment, the cycle time wasmanually set, but with the second embodiment the cycle time isautomatically changed according to subject brightness. Also, imaging andimage display are also repeatedly executed at intervals of the cycletime for the case of long time exposure.

The structure of the second embodiment is substantially the same as thestructure of the first embodiment shown in FIG. 1 to FIG. 3, and theflowcharts shown in FIG. 4 to FIG. 7 are simply changed to theflowcharts shown in FIG. 13 to FIG. 15, with description centering onpoints of difference. The setting unit 298 of FIG. 3 is not manually setusing the information setting dial 24 in the second embodiment, but isautomatically set by the body CPU 251 etc.

FIG. 13 shows a power on reset operation performed by the body CPU 251at the camera body 200 side. This flowchart has the same flow as theflowchart for power on reset shown in FIG. 4, except that the subroutinefor cycle time input of step #31 is omitted, and so the same referencenumerals will be used for the same steps, and detailed description willbe omitted.

In the first embodiment, the cycle time input subroutine of step #31 wasexecuted in order to manually set cycle time, but in the secondembodiment the cycle time is automatically set based on subjectbrightness etc. and so step #31 is omitted. The shooting operationsubroutine of step #37 is the same as the flowchart of FIG. 6 for thefirst embodiment.

Next, an exposure operation of step #75 within the sub-routine for theshooting operation of step #37 will be described using FIG. 14. If thisexposure operation subroutine is entered, it is determined whether ornot the exposure mode is bulb mode (#101). If the result ofdetermination is that it is not bulb mode, it is then determined whetheror not it is a long time exposure (#102). Regarding whether or not it isa long time exposure, a long time exposure is determined if the shutterspeed read in step #7 exceeds 30 second for example.

If the result of determination is that it is not a long time exposure,normal exposure is carried out. This normal exposure operation is thesame as from step #103 to step #115 of FIG. 7, and the same steps havethe same reference numerals, with detailed description thereof beingomitted.

If the result of determination in step #101 is that bulb mode has beenset, 0.5 seconds, for example, is set as an initial value for the cycletime (#118). Also, if the result of determination in step #102 is that along exposure time has been set, the cycle time is set according to theset shutter speed (#117). As setting of the cycle time here, the cycletime is made 1/100th of the set shutter speed, for example.

If setting of cycle time is carried out in step #117 or step #118, thennext the added image storage region of the temporary storage section 293is cleared (#120), a timer for cycle time timing is started (#121), andimaging on the image sensor 221 is commenced (#123).

It is then determined whether or not the time of the time for cycle timetiming has reached the set cycle time (#125). If the result ofdetermination is that the cycle time has not elapsed, it is determinedwhether completion of bulb exposure has been instructed (that is,whether full pressing of the release button 21 has been released and the2R switch turned off) (#151).

If the result of determination in step #151 is that the 2R switch isstill on, it is determined whether the time set by the long timeexposure has elapsed (#152). If the result of determination is that theset time has not elapsed, step #125 is returned to. In this way, in thecase where the 2R switch is still on with both the cycle time and theset long time not elapsed, a standby state is entered where thedeterminations of steps #125, #151 and #152 are repeated.

If the result of determination in step #125 is that the cycle time haselapsed, then similarly to from step #127 to #139 in FIG. 7, imageforming of the image sensor 221 is stopped with the shutter 213 stillopen (#127), and reading of pixel signals is carried out (#129).

Next, image data based on the read out pixel signals is temporarilystored in the temporary storage section 293 (#131), and after the timerfor cycle time timing is restarted (#133) imaging is commenced (#135).Addition of temporarily stored image data and previously added imagedata is then carried out (#137), and this added image is stored again inthe added image storage region of the temporary storage section 293(#138), and then displayed (#139).

In this way, every time it is determined in step #125 that the cycletime has elapsed, similarly to the case of the first embodiment,together with reading of pixel signals from the image sensor 221, imagedata based on the image signals is stored in a storage region of thetemporary storage section 293, and an overall added image is generatedand displayed.

If display of the added image is carried out, next, similarly to step#102, it is determined whether or not there is a long time exposure(#141). If the result of determination is that there is a long timeexposure, processing returns to step #125 and the operations describedabove are executed. On the other hand, if there is not a long timeexposure, that is, in the event that bulb mode has been set, resettingof the cycle time is carried out (#143).

Cycle time when bulb mode has been set is set at an initial value instep #118, but this cycle time is subjected to automatic adjustment instep #143 so that cycle time is shortened when subject brightness ishigh, or extended when subject brightness is low. A subroutine forresetting of this cycle time will be described later using FIG. 15. Onceresetting of cycle time has been carried out step #125 is returned to.

If the result of determination in step #151 is that there is a bulbexposure completion instruction, or if the result of determination instep #152 is that the set time has elapsed, processing for completingthe exposure operation is carried out in steps #153 to #161. These stepsare the same as FIG. 7, and the same steps have the same referencenumerals, with detailed description thereof being omitted.

Next, a subroutine for resetting cycle time in step #143 will bedescribed using FIG. 15. If this subroutine for resetting cycle time isentered, determination of brightness level is carried out (#181). As thebrightness level, an average brightness of image data read out in step#129 is used. Generally, if brightness of each pixel of image data hasan 8-bit resolution, the brightness level of each pixel is from 0 to255. Average brightness is an average of those brightness levels foreach pixel. Besides average brightness, it is also possible toappropriately use other metered calculations, such center-weightedbrightness.

Using the obtained brightness level, prediction of exposure time is thencarried out (#183) until correct exposure is attained. Here, correctexposure assumes the case where average of brightness level of eachpixel is, for example, about 140. Accordingly, if the current averagebrightness level and the time taken to reach that brightness level areknown, it is possible to estimate the time taken to attain correctexposure. If estimated time is obtained, calculation of cycle time isnext carried out (#185).

As this calculation, for example, similarly to step #117, the estimatedtime is divided by 100. Cycle time is update based on the time obtainedhere (#187), and the original routine is returned to. If the processingflow for the exposure operation shown in FIG. 14 is returned to, in step#125 determination is made using the re-set cycle time, and imaging anddisplay are carried out at this time interval.

In this way, in the second embodiment of the present invention, when inbulb mode it is possible to automatically re-set the cycle timeaccording to subject brightness. It is therefore possible to carry outdisplay updating at an effective timing according to subject brightness.Also, with a long exposure time, cycle time is automatically setaccording to the set time. It is therefore possible to carry out displayupdating at an effective timing according to the set time.

The set cycle time in steps #117 and step #120 are only examples, andcan be appropriately changed. Also, with respect to the determination asto whether or not there is a long time exposure in step #102, thedetermination value for whether or not there is a long time can also beappropriately changed. Further, regarding setting of the cycle time instep #117, besides setting the cycle time simply by division, it is alsopossible to adopt various methods, such as, for example, dividing thelong time into zones, and determining a set time for each zone.

In the first and second embodiments of the present invention, in thecase of exposure in bulb mode or over a long time, the imaging section291 is repeatedly operated at intervals of the cycle time, image datarepeatedly output from the imaging section 291 is sequentially added,added image data is generated, and image display is carried out based onthis added image data. The cycle time is set either manually orautomatically. It is therefore possible to perform display update at aneffective timing, and it is possible for the photographer to confirm theappearance of the shot as imaging progresses in bulb mode or over a longtime.

Next, a third embodiment of the present invention will be describedusing FIG. 16 to FIG. 20. In the first and second embodiments, an addedimage was displayed from the start. However, for a short while aftercommencing exposure the screen will remain black and the photographer isunable to confirm whether or not exposure is being carried out, and mayfeel uneasy. With the third embodiment, in order to make it possible forthe photographer to confirm that the exposure is in progress even in aperiod where the brightness level of a subject image immediately afterstarting the exposure is low, a notification display is carried out toshow that bulb exposure etc. is in progress.

The structure of the third embodiment is partially similar to thestructure of the first embodiment, and so parts of the structure thatare the same will have detailed description omitted.

The external appearance of a digital single lens reflex camera of thethird embodiment of the present invention is the same as in FIG. 1.Electrical circuits of this digital single lens reflex camera are shownin FIG. 16. Compared to the electrical circuits of the first embodiment(refer to FIG. 2), the third embodiment differs only in that thetemperature measurement circuit 231 has been omitted. This is because inthis embodiment, the function of determining an upper limit for cycletime according to surrounding temperature is omitted. In this embodimentalso, it is obviously also possible to determine an upper limit of cycletime according to surrounding temperature, similarly to the first andsecond embodiments.

FIG. 17 shows a structure relating to image display during exposure, forbulb exposure. Compared to the first embodiment (refer to FIG. 3) thereis a difference in that the setting section 298 is omitted. Naturally,the setting section 298 is also provided in the third embodiment, but asit is not important it has been omitted from FIG. 17.

With this type of arrangement, the control section 297 performs controlso that image data that has been acquired by the imaging section 291 issequentially added by the adding processing section 294 every set cycletime, and this added image is displayed on the image display section296. Display by the rear surface liquid crystal monitor 26 at the timeof bulb exposure involves first displaying notification information 320a at the time of starting bulb exposure (FIG. 20( a)), and displayingonly notification information 320 b within a specified period after that(FIG. 20( b)).

Also, image data is cumulatively added from the start of exposure, andan added image for bulb exposure is displayed once a specifiedbrightness level has been reached, as shown in FIG. 20( c). At the stageof FIG. 20( c) the exposure time is insufficient and so the image isdark, but after that if the image gradually changes to a brighter imageand images are repeatedly cumulatively added a number of times, it willbecome an image that appears over exposed, as shown in FIG. 20( g). Thenotification information 320 c to 320 g is also displayed in asuperimposed manner during display of the added images. If thisnotification information 320 c to 320 g is also present during executionof bulb exposure, the elapsed time for the bulb exposure is displayed.

Next, detailed operation of the digital single lens reflex camera of thethird embodiment of the present invention will be described using theflowcharts shown in FIG. 18 and FIG. 19. In the third embodiment also,if a battery is fitted, the processing flow for power on reset isexecuted. The processing flow for this power on reset is the same as inFIG. 4 for the first embodiment, and so detailed description will beomitted.

Processing flow for the cycle time input of step #31 in the processingflow of the power on reset (refer to FIG. 4) will be described usingFIG. 18. The processing flow for this cycle time input differs from theprocessing flow of the cycle time input of the first embodiment (referto FIG. 5) only in that step #41 (temperature detection) and step #43(determination of cycle time upper limit value) are omitted. Asdescribed above, with this embodiment the temperature measurementcircuit 231 is omitted, which means that steps #41 and #43 are omittedfrom the processing flow for cycle time input.

With this embodiment, the determination as to whether or not the cycletime has reached an upper limit at step #55 can be appropriately set,but it is possible, for example, to make 9 minutes a length of time thatwill not be affected by dark current. Apart from this, it is the same asthe processing flow (FIG. 5) for cycle time input of embodiment one, andso detailed description will be omitted.

Next, the shooting operation of step #37 in the processing flow of thepower on reset (refer to FIG. 4) is the same as the processing flow ofthe shooting operation in the first embodiment (refer to FIG. 6) and sodetailed description is omitted.

Next, the exposure operation of step #75 in the processing flow for theshooting operation will be described using FIG. 19. In the description,steps carrying out the same processing as the flow of FIG. 7 for thefirst embodiment have the same step numbers attached, and detaileddescription thereof is omitted.

If the exposure operation processing flow is entered, it is firstdetermined whether or not bulb mode has been set (#101). If the resultof this determination is that bulb mode has not been set, normalexposure mode, such as program exposure mode, is executed in steps #103to #115. This normal exposure mode processing is the same as for theflow of FIG. 7, and so detailed description is omitted.

If the result of determination in step #101 is that bulb mode has beenset, then first the added image storage region that has been allocatedinside the temporary storage section 293 is cleared (#119), and thecycle time that was manually input in step #31 is set (#120A). Next, atimer for display cycle time timing is started (#121), and similarly tostep #105, together with opening of the shutter 213 imaging is commenced(#123).

Display of notification information such as is shown in FIG. 20( a) isthen started (#124). That is, at the time bulb exposure commences, thescreen is jet black, and if there is no display at all the photographerwill be unsure as to whether or not the exposure using bulb exposure hasstarted. In this embodiment therefore, by displaying the notificationinformation 320 a it is possible for the photographer to recognize thatthe exposure has started.

If the display of notification information has started, it is firstdetermined whether or not the timer for cycle time timing has reachedthe cycle time set in step #120A (#125). If the result of determinationis that the cycle time has not elapsed, it is determined whether or notthe full pressing of the release button 21 has been released, that is,whether or not the 2R switch is off (#151). In the event that the 2Rswitch is on and the cycle time has not elapsed, a standby state isentered where the determinations at steps #125 and #151 are alternatelyexecuted.

If the result of determination in step #125 is that the cycle time haselapsed, then similarly to step #109 and step #111, image forming of theimage sensor 221 is stopped with the shutter 213 still open, and readingof pixel signals is carried out (#127, #129).

Next 1 is added to the update counter (#130A). The update counter isreset at the same time as the timer is started in step #121, and everytime this step #130A is passed through 1 is added. By multiplying acount value of this update counter by the cycle time set in step #120A,it is possible to obtain a cumulative time from when the exposure usingbulb exposure started.

Next, the timer for cycle time timing is restarted (#131A), and imagingon the image sensor 221 is commenced (#133A).

Next, added image data is read from a storage region that was previouslystored in the storage region of the temporary storage section 293 andadding processing for this image data and image data read out in step#129 is carried out (#135A). Image data of the added image obtained hereis stored in a storage region of the temporary storage region 293 thatis used for added image storage (#137A).

If accumulation of added images is completed, determination ofbrightness level is then carried out (#139A). The brightness level isdetermined based on image data read out in step #129. In thisembodiment, since pixel signals are digitalized at a resolution of8-bits, it is possible for the charge accumulation amount for each pixelto be expressed by a number from 0-255. This charge accumulation amountcorresponds to the subject brightness level corresponding to that pixel,which means that if an average value for all pixels is obtained abrightness level for image data is obtained.

Next, it is determined whether or not the brightness level obtained instep #139A has reached a predetermined brightness level (#141A). In thisembodiment the specified brightness level is made 20. The specifiedbrightness level can obviously be appropriately varied according to howthe added image display appears.

If the result of determination in step #141A is that the predeterminedbrightness level has not been reached, the notification information 320b, as shown in FIG. 20( b) is displayed (#147A). At this stage, theexposure amount from bulb exposure is insufficient, and it can beconsidered that even if the added image is displayed the screen will beunintelligible, and so, as shown in FIG. 20( b), the fact that bulbexposure is in progress and an elapsed time from the start of bulbexposure, are displayed.

This elapsed time is calculated based on a count value of the updatecounter obtained in step #130A, and set cycle time. If the display ofnotification information 320 b is carried out, step #125 is returned to,and the previously described operations are executed. There is also noproblem in providing a counter for obtaining cumulative exposure timewhen using bulb exposure, and displaying elapsed time based on thiscounter.

If the result of determination in step #141A is that the predeterminedbrightness level has been reached, an added image that has been added instep #135A is displayed (#143A). Specifically, by executing from step#125 to step #147A once or a plurality of times, the brightness level ofthe added image improves. If the result of determination is that thebrightness level has reached the predetermined level, then since theimage from bulb exposure has reached a level at which it can bedisplayed, an added image is displayed on the rear surface liquidcrystal monitor 26.

The notification information 320 c to 320 g, as shown in FIG. 20( c) toFIG. 20( g), is displayed superimposed on the added image (#145A). Thenotification information 320 c to 320 g here is display of the fact thatthere is a bulb exposure, together with the elapsed time fromcommencement of the bulb exposure. The added image and the notificationinformation continue to be displayed until the next cycle time haselapsed. If display is carried out, step #125 is returned to, and thepreviously described steps are executed.

If the result of determination in step #151 is that the full pressing ofthe release button 21 has been released, that is, it has been determinedthat the 2R switch has been turned off, then similarly to step #127imaging is stopped together with closing of the shutter 213 (#153).Specifically, the exposure operation is completed, and after that theoriginal routine is returned to.

In this way, imaging by the image sensor 221 is stopped and image dataoutput every time the cycle time that was set in step #31 (#120A)elapses (Y at #125). Addition processing for this image data and theprevious added image being stored in the storage region of the temporarystorage section 293 is carried out, and the result is stored in thestorage region of the temporary storage section 293. The added imagestored in each storage region is updated and displayed in the rearsurface liquid crystal monitor 26 every time the cycle time elapses, asshown in FIG. 20. At the initial stages of exposure, since exposureamount is small an added image is not displayed. After that, bycumulatively adding image data every time the cycle time elapses, theimage gradually becomes brighter. If image brightness reaches apredetermined level, an added image is displayed from then on.

Also, in this embodiment if bulb mode has been set, at the time ofstarting an exposure using bulb exposure an image acquired from theimage sensor 221 is not displayed, and instead notification information320 a, 320 b indicating that bulb exposure is in progress is displayed.It is therefore possible for the photographer to easily recognize thatthe exposure operation is progressing, even in a period where thebrightness level of the image after exposure has started is low.

Further, in this embodiment, the fact that the elapsed time since thestart of bulb exposure is displayed is extremely useful.

Next, a fourth embodiment of the present invention will be describedusing FIG. 21 and FIG. 22. In the third embodiment, if the added imagereaches a predetermined brightness level display of the added image iscarried out, but with the fourth embodiment only the notificationdisplay 321 a is displayed until an initial cycle time elapsed, and ifthe initial cycle time elapses and an image is read, the image isdisplayed.

The structure of the fourth embodiment is the same as that of the thirdembodiment, the flowcharts shown in FIG. 4, FIG. 6, and FIG. 18 are alsothe same, and the exposure information display shown in FIG. 10 and thecycle time display shown in FIG. 11 are also the same. The point ofdifference is that the flowchart showing the exposure operation shown inFIG. 19 is replaced with the flowchart in FIG. 21, and description willcenter on this difference. Each of the steps within the flowchart shownin FIG. 21 that are the same as the steps in the flowchart shown in FIG.19 have the same reference numerals attached, and detailed descriptionthereof is omitted.

If the processing flow for the exposure operation is entered, it isdetermined whether or not it is bulb mode (#101), and in the event thatbulb mode has not been set, then similarly to the third embodiment shownin FIG. 19, a normal exposure mode, such as program exposure mode, iscarried out. On the other hand, if bulb mode has been set, thensimilarly to the third embodiment from step #119 to step #123 isexecuted. Next, notification display for bulb exposure is carried out(#124 a). This notification display can be the same display as in FIG.20( a), but in this embodiment notification display 321 a as shown inFIG. 22( a) is carried out.

If the notification display 321 a for bulb exposure is carried out, itis next determined whether or not the cycle time has elapsed (#125). Ifthe result of determination is that the cycle time has not elapsed, thensimilarly to the third embodiment a state is entered where thedeterminations at steps #125 and #151 are alternately executed. On theother hand, if the cycle time has elapsed, then similarly to the thirdembodiment from step #127 to step #137A are executed.

After that, in the third embodiment determination of the brightnesslevel of the added image etc. was carried out, but with this embodimentdisplay of the added image is carried out regardless of the brightnesslevel (#143A). Specifically, since the cycle time has elapsed andreading of an image from the image sensor 221 is carried out, this readimage is displayed immediately. The notification information 321 b and320 c to 320 g, as shown in FIG. 22( b) to FIG. 22( g), is thendisplayed superimposed on the added image (#145A).

If the added image and the notification information 321 b and 320 c to320 g is displayed, step #125 is returned to, the previously describedoperations are executed, and similarly to the first embodiment the addedimage and the notification displays 321 b and 321 c to 320 g are updatedand displayed every time the cycle time elapses.

If the 2R switch is turned off, then as with the third embodiment theshutter is closed, the imaging operation is stopped, and the originalroutine is returned to.

In this way, with the fourth embodiment of the present invention apredetermined period from start of the bulb exposure displays that thebulb exposure is being executed. It is therefore possible for thephotographer to easily recognize that the exposure is being carried outimmediately after commencement of bulb exposure. Also, if an image isread out after the initial cycle time has elapsed, the acquired image isimmediately displayed, which means that it is possible to confirm theexposure state using bulb exposure from the initial stage.

In the fourth embodiment, at the point in time where the cycle timeinitially elapses, an image read from the image sensor 221 is displayed,but it is also possible to have an arrangement where an image isdisplayed at the point in time where the cycle time elapses a second andsubsequent time, and only a notification display is displayed up tothen.

With the third and fourth embodiments of the present invention, aspecified period from start of the bulb exposure displays that the bulbexposure is being executed on the rear surface liquid crystal monitor26, which is a display section. It is therefore possible for thephotographer to easily recognize that the exposure operation isprogressing, even in a period where the brightness level of the exposedimage immediately after exposure has started is low.

In the third and fourth embodiments, as notification information thereare display indicating bulb exposure and display of the elapsed timefrom the start of bulb exposure, but it is also possible to omit theelapsed time. Also, the characters “bulb exposure” and “BULB” aredisplayed in order to indicate that bulb exposure has commenced, butthis is not limiting and it is also possible to have another displaysuch as a symbol or an icon.

Also, with the third and fourth embodiments in the case where theexposure operation is completed, if imaging is stopped in step #153(FIG. 19, FIG. 21) the original routine is returned to. However, becausethe imaging section 291 accumulates signal charge on the image sensor221, it is also possible, similarly to step #155 in FIG. 7 of the firstembodiment, to read these signals, generate an added image, and displaythe added image.

Further, with the third and fourth embodiments, when bulb mode has beenset added images are generated, but it is also possible to generate anddisplay added images in the case where long time exposure is carriedout, for example, exposure of a few seconds. This approach can also besimilarly adopted in other embodiments.

Still further, with the third and fourth embodiments, in step #31 thecycle time is manually set, but this is not limiting and it is alsocompletely possible, similarly to the second embodiment for example, toautomatically set the cycle time according to subject brightness, so asto either shorten the cycle time if the brightness is high, orconversely to extend the cycle time if the brightness is low.

Next, a fifth embodiment of the present invention will be describedusing FIG. 23 to FIG. 27. In the first to fourth embodiments, becauseadded images etc. are displayed at the time of a long time exposure suchas bulb exposure, the rear surface liquid crystal monitor 26 was in adisplay state during long time exposure However, bulb exposure lastsover a comparatively long time, which means that the photographer mustwatch the display screen the entire time. Also, a display device forimage display used with an imaging device such as a camera hascomparatively high power consumption, and so if the display state ismaintained during execution of bulb exposure the power supply batterieswill be used up in a short time.

With this embodiment therefore, in connection with update of an addedimage, the display screen is only illuminated for a predetermined time,and for a long time exposure such as bulb exposure the photographer canobserve without becoming fatigued.

The structure of the fifth embodiment is partially similar to thestructure of the first and third embodiments, and so detaileddescription of parts of the structure that are the same will be omitted.

FIG. 23 is an external perspective drawing looking at a digital singlelens reflex camera of the fifth embodiment from a rear surface side. Itis different from the digital single lens reflex camera of the firstembodiment shown in FIG. 1 only in that an LED (Light Emitting Diode) 41for bulb display is arranged.

Specifically, a bulb display LED (Light Emitting Diode) 41 is arrangedclose to the viewfinder eyepiece on the rear surface of the camera body200. This bulb display LED 41 is lit up during execution of bulbexposure, and shows that bulb exposure is in progress to the user. Theremaining members are the same as for the digital single lens reflexcamera shown in FIG. 1, and the same members have the same referencenumerals, with detailed description being omitted.

FIG. 24 is a block diagram showing electrical circuits of the digitalsingle lens reflex camera of the fifth embodiment. Compared to theelectrical circuits of the first embodiment (refer to FIG. 2), the fifthembodiment differs only in that the temperature measurement circuit 231has been omitted, and the display LED 41 and a liquid crystal monitorbacklight 26 a are added.

The omission of the temperature measurement circuit 231 is the same asin the third embodiment shown in FIG. 16. Also, the display LED 41connected to the data bus 252 is lit up in response to a light upcommand from the body CPU 251, and turned off in response to a turn offcommand.

The liquid crystal monitor backlight 26 a for illuminating the rearsurface liquid crustal monitor 26 is arranged at the rear surface sideof the rear surface liquid crystal monitor 26, and is drive controlledby the liquid crystal monitor drive circuit 263. The structure otherthan for the points of difference described above is the same as for thefirst embodiment shown in FIG. 2, and so detailed description will beomitted.

FIG. 25 shows a structure relating to image display during exposure, forbulb exposure. Compared to the first embodiment (refer to FIG. 3) thereis a difference in that a display illumination section 296 a and anotification section 299 are provided.

Specifically, the display illumination section 296 a is comprised of theliquid crystal monitor backlight 26 a and the liquid crystal monitordrive circuit 263, and performs illumination of the image displaysection 296, so it is possible for the photographer to easily observethe image display section 296 even in a dark place. The notificationsection 299 is comprised of the display LED 41 etc., which is lit upduring bulb exposure to notify the photographer. The notificationsection 299 is not limited to an LED, and can be another display elementsuch as a lamp.

With this type of arrangement, the control section 297 performs controlso that image data that has been acquired by the imaging section 291 issequentially added by the adding processing section 294 every set cycletime, and this added image is displayed on the image display section296. Display on the rear surface liquid crystal monitor 26 at the timeof bulb exposure is first displaying notification information 330 a onthe rear surface liquid crystal monitor 26 at the time of commencementof bulb exposure (FIG. 27( a)), and the notification section 299lighting up.

Also, image data from the start of exposure is cumulatively added, andan added image is displayed on the rear surface liquid crystal monitor26 every time the cycle time elapses, as shown in FIG. 27( b) to FIG.27( g). At the stage of FIG. 27( b) the exposure time is insufficientand so the image is dark, but after that if the images are repeatedlycumulatively added a number of times it gradually changes to a brighterimage, it will become an image that appears slightly over exposed, asshown in FIG. 27( g).

Further, at the time the cycle time elapses, the image display section296 is illuminated by the display illumination section 296 a from thetime of update for a predetermined time, and it possible to easily viewthe added image displayed on the rear surface liquid crystal monitor 26.If a predetermined time elapses, illumination by the displayillumination section 296 a is turned off, and after that if the cycletime elapses again illumination by the display section illuminationsection 296 a is recommenced. In this way, it is possible for thedisplay illumination device 296 a to not always be on, and to reducepower consumption. Also, during bulb exposure, since the notificationsection 299 is always in a display state, it is possible for thephotographer to easily confirm that the bulb exposure is being executed.

Next, detailed operation of the digital single lens reflex camera of thefifth embodiment of the present invention will be described using theflowchart shown in FIG. 26. In the fifth embodiment also, if a batteryis fitted, the processing flow for power on reset is executed. Theprocessing flow for this power on reset is the same as in FIG. 4 for thefirst embodiment, and so detailed description will be omitted.

Also, cycle time input of step #31 in the processing flow of the poweron reset (refer to FIG. 4) is the same as the processing flow of thecycle time input in the third embodiment (refer to FIG. 18) and sodetailed description is omitted. Also, the shooting operation of step#37 in the processing flow of the power on reset (refer to FIG. 4) isthe same as the processing flow of the shooting operation in the firstembodiment (refer to FIG. 6) and so detailed description is omitted.

Next, the exposure operation of step #75 within the shooting operationprocessing flow (FIG. 6) will be described using FIG. 26. In thedescription, steps carrying out the same processing as the flow of FIG.7 for the first embodiment have the same step numbers attached, anddetailed description thereof is omitted.

If this processing flow is entered, first, similarly to step #9 (referto FIG. 4), it is determined whether or not bulb mode has been set(#101). If the result of determination is that bulb mode has not beenset, normal exposure mode, such as program exposure mode, is executed.Processing in normal exposure mode of step #103 to step #115 is similarto that of the first embodiment shown in FIG. 7, and so detaileddescription will be omitted.

If the image display of step #115 is carried out there is display of anexposed image and the liquid crystal monitor backlight 26 a is lit up,to illuminate the rear surface liquid crystal monitor 26 (#116). Iflighting up of the liquid crystal monitor backlight 26 a is carried out,the original routine is returned to.

If the result of determination in step #101 is that bulb mode has beenset, then the added image storage region that has been allocated insidethe temporary storage section 293 is cleared (#118B), and the cycle timethat was manually input in step #31 is set (#119B). Next, a timer fordisplay cycle time timing is started (#120B), and similarly to step#105, together with opening of the shutter 213 imaging is commenced(#121B).

Next, the bulb display LED 41 is lit up, to display the fact that thebulb exposure has commenced (#122B). This bulb display LED 41 is alwayskept on during bulb exposure, until it is turned off in step #173B,which will be described later.

Display of notification information 330 a for bulb exposure, such as isshown in FIG. 27( a) is then started (#123B). That is, at the time bulbexposure commences, the screen is jet black, and if there is no displayat all the photographer will be unsure as to whether or not the exposureusing bulb exposure has started. In this embodiment therefore, bydisplaying the notification information 330 a it is possible for thephotographer to recognize that the exposure has started. Next, theliquid crystal monitor backlight 26 a is lit up (#124B) to illuminatethe rear surface liquid crystal monitor 26, making it possible for thephotographer to easily view the added image.

If the backlight is lit up, it is next determined whether or not thetimer for cycle time timing has reached the cycle time set in step #119(#125). If the result of determination is that the cycle time has notelapsed, it is determined whether or not the full pressing of therelease button 21 has been released, that is, whether or not the 2Rswitch is off (#151).

If the result of determination in step #151 is that the 2R switch isoff, it is determined whether or not 10 seconds has elapsed fromcommencement of lighting up the liquid crystal monitor backlight 26 a(#155B). In this embodiment, a time is provided that starts a timingoperation in synchronization with lighting up of the liquid crystalmonitor backlight 26 a, and in this step determination is made based onthe time measured by this timer.

If the result of determination in step #155B is that 10 second has notelapsed, then step #125 is returned to and a standby state is enteredwhere the determinations of step #125, step #151 and step #155 arerepeatedly carried out. On the other hand, if the result ofdetermination in step #155B is that 10 second have elapsed, then it isdetermined whether or not the cycle time that was set in step #119B is30 seconds or more (#157B). If the result of determination is less than30 seconds, processing returns to step #125 and the operations describedabove are executed.

On the other hand, if the result of determination in step #157B is thatthe set cycle time is 30 seconds or more, illumination by the liquidcrystal monitor backlight 26 a is turned off (#159B). In thisembodiment, if the set cycle time is 30 seconds or more, then every timethe added image is updated the liquid crystal monitor backlight 26 a islit up for 10 seconds, and the rear surface liquid crystal monitor 26 isilluminated. Once 10 seconds elapses, the liquid crystal monitorbacklight 26 a is turned off. Also, if the set cycle time is less than30 seconds, the liquid crystal monitor backlight 26 a is kept turned on.

In step #157B, determining whether or not to turn off the backlightaccording to the set cycle time is because if the length of time thebacklight is on is made 10 seconds, in the event that the set cycle timeexceeds 10 seconds but is less than 30 seconds the backlight will berepeatedly turned on and off in a short period of time, causingillumination flicker, and making it difficult to view the screen of therear surface liquid crystal display monitor 26. The set time in step#157B (30 seconds) and the set time in step #155 (10 seconds) are onlyillustrative examples, and they can be appropriately changed taking intoconsideration reducing power supply consumption and ease of viewing thedisplay.

If the result of determination in step #125 is that the cycle time haselapsed, then similarly to step #109 and step #111, image forming of theimage sensor 221 is stopped with the shutter 213 still open, and readingof pixel signals is carried out (#127, #129). Next, the timer for cycletime timing is restarted (#130B), and imaging on the image sensor 221 iscommenced (#131B).

Next added image data is read from a storage region that was previouslystored in the storage region of the temporary storage section 293, andadding processing for this image data and image data read in step #129is carried out (#133B). Image data of the added image obtained here isstored in a storage region of the temporary storage region 293 that isused for added image storage (#135B).

An added image that has been added in step #135B is then displayed onthe rear surface liquid crystal monitor 26 (#137B), the liquid crystalmonitor backlight 26 a is lit up, and the rear surface liquid crystalmonitor 26 is illuminated (#139B). If lighting up of the backlight iscarried out, step #125 is returned to, and the previously describedoperations are executed By executing from step #125 to step #139B aplurality of times, the brightness level of the added image improves, asshown in FIG. 27( b) to FIG. 27( g).

The photographer will release the full pressing of the release button 21when the added image displayed on the rear surface liquid crystalmonitor 26 reaches an appropriate level or the level desired by thephotographer. Specifically, if the result of determination in step #151is that it has been determined that the 2R switch has been turned off,then similarly to step #127 imaging is stopped together with closing ofthe shutter 213, and the exposure operation is completed (#161B).

If imaging is stopped, next, similarly to step #129, reading of imagedata from the image sensor 221 is carried out ((#163B), and similarly tostep #133 the image read out this time is added to the previous addedimage (#165B). After this, similarly to step #135, the added image istemporarily held (#167B) and the added image is displayed on the rearsurface liquid crystal monitor 26 (#169B).

In this embodiment, at the point in time where a finger is taken awayfrom the release button 21 and the bulb exposure is completed, imagesignals accumulated in the image sensor 221 are read out, these imagesignals are added to the previous added image, and that added image isdisplayed. If display of the added image is carried out, the liquidcrystal monitor backlight 26 a is turned on, and the rear surface liquidcrystal monitor 26 is illuminated (#171B), and the bulb display LED 41is turned off upon completion of the bulb exposure (#173B).

In this way, with this embodiment imaging by the image sensor 221 isstopped and image data output every time the cycle time that was set instep #119B elapses (Y at #125). Addition processing for this image dataand the previous added image being stored in the storage region of thetemporary storage section 293 is carried out, and the result is stored.The added image stored in each storage region is updated and displayedin the rear surface liquid crystal monitor 26 every time the cycle timeelapses, as shown in FIG. 27, and it is possible to observe the exposurestate for bulb exposure in real time.

Also, with the fifth embodiment of the present invention, if the cycletime elapses and the image is updated, the liquid crystal monitorbacklight 26 a is turned on for a predetermined time (10 seconds in thisembodiment). The liquid crystal monitor backlight 26 a for the rearsurface liquid crystal monitor 26 is not always kept on during bulbexposure, which means it is possible to reduce power consumption.Further, lighting of the liquid crystal monitor backlight 26 a is at theimage cycle time, which means that the photographer can observe theimage with interest.

Further, with the fifth embodiment of the present invention, in theevent that the set cycle time is less than a predetermined time (30seconds in this embodiment), lighting of the liquid crystal monitorbacklight 26 a is carried out continuously. Therefore, turning on andoff of the backlight is not repeated at short intervals and there is novisually annoying flicker.

Also with the fifth embodiment of the present invention, the LED forbulb display is lit once the bulb exposure is commenced, and once bulbexposure is completed the bulb display LED 41 is turned off. It istherefore possible to easily confirm whether or not the bulb exposure isin progress, which is extremely useful.

Next, a sixth embodiment of the present invention will be describedusing FIG. 28. With the fifth embodiment of the present invention, ifthe added image is updated, the liquid crystal monitor backlight 26 a isturned on for a predetermined time (10 seconds), and if thepredetermined time elapses the liquid crystal monitor backlight 26 a isturned off. In the sixth embodiment, a backlight button is provided, andthe liquid crystal monitor backlight 26 a is turned on if this backlightbutton is operated.

The structure of the sixth embodiment is the same as that of the fifthembodiment shown in FIG. 23 to FIG. 25, the flowcharts shown in FIG. 4,FIG. 6, and FIG. 18 are also the same, and bulb mode exposure timedisplay shown in FIG. 27, the exposure information display shown in FIG.10 and the update display shown in FIG. 11 are also the same. The pointof difference is that the flowchart showing the exposure operation shownin FIG. 26 is replaced with the flowchart in FIG. 28, and descriptionwill center on this difference. Each of the steps within the flowchartshown in FIG. 28 that are the same as the steps in the flowchart shownin FIG. 26 have the same reference numerals attached, and detaileddescription thereof is omitted.

If the processing flow for the exposure operation is entered, it isdetermined whether or not it is bulb mode (#101), and in the event thatbulb mode has not been set, then similarly to the fifth embodiment shownin FIG. 26, a normal exposure mode, such as program exposure mode, iscarried out. On the other hand, if bulb mode has been set, thensimilarly to the fifth embodiment from step #118B to step #124B areexecuted. At this time, lighting up of the bulb display LED 41 and theliquid crystal monitor backlight 26 a is also the same as with the fifthembodiment.

If the backlight is lit up, it is next determined whether or not thecycle time has elapsed (#125). If the result of determination is thatthe cycle time has not elapsed, then similarly to the fifth embodimentit is determined in step #151 whether or not the 2R switch is off. Ifthe result of determination is that the 2R switch is off, then similarlyto the fifth embodiment steps #161 and after are executed.

On the other hand, if the result of determination in #151 is that the 2Rswitch is not off, it is determined whether or not the backlight buttonis on (#152B). The backlight button can be a dedicated button providedon the rear surface of the camera body 200, but in this embodiment theOK button 31 is also used for this function. Specifically, determinationas to whether or not the OK button 31 has been operated is carried out.If the result of determination is that the backlight button is on, theliquid crystal monitor backlight 26 a is lit.

When the liquid crystal monitor backlight 26 a is lit in step #153B, theadded image is not updated. After lighting the backlight, if the imagecycle time elapses within 10 seconds, the added image is then alsoupdated. In the event that the backlight is lit, or the backlight buttonwas not on in step #152B, steps #155B and after are executed, as in thefifth embodiment.

In this way, with the sixth embodiment, the backlight button isprovided, and the liquid crystal monitor backlight 26 a is turned on ifthis backlight button is operated. It is therefore possible toilluminate the rear surface liquid crystal monitor 26 and easily confirmthe added image by operating the backlight button, even after initiallylighting the liquid crystal monitor backlight 26 a and then turning itoff when a predetermined time has elapsed.

Next, a seventh embodiment of the present invention will be describedusing FIG. 29. In the fifth embodiment and the sixth embodiment, theadded images are only updated at set cycle time intervals, and betweenthe cycle times it is not possible to confirm the state of progress ofthe bulb exposure. With the seventh embodiment, an update button isprovided, and if this update button is operated update of the image iscarried out together with lighting of the backlight.

The structure of the seventh embodiment is the same as that of the fifthembodiment shown in FIG. 23 to FIG. 25, the flowcharts shown in FIG. 4,FIG. 6, and FIG. 18 are also the same, and bulb mode exposure timedisplay shown in FIG. 27, the exposure information display shown in FIG.10 and the update display shown in FIG. 11 are also the same. The pointof difference is that the flowchart showing the exposure operation shownin FIG. 26 is replaced with the flowchart in FIG. 29, and descriptionwill center on this difference. Each of the steps within the flowchartshown in FIG. 29 that are the same as the steps in the flowchart shownin FIG. 26 have the same reference numerals attached, and detaileddescription thereof is omitted.

If the flowchart for the exposure operation is entered, then similarlyto the fifth embodiment it is determined in step #125 whether or not thecycle time has elapsed. If the result of determination is that the cycletime has elapsed, then similarly to the fifth embodiment step #127 andafter are executed.

On the other hand, if the result of determination in #125 is that thecycle time has not elapsed, it is determined whether or not the 2Rswitch is off (#151). If the result of determination is that the 2Rswitch is off, then similarly to the fifth embodiment steps #161B andafter are executed. On the other hand, if the result of determination isthat the 2R switch is not in off, it is then determined whether or notthe update button is on (#154B).

The update button can be a dedicated button provided on the rear surfaceof the camera body 200, but in this embodiment the OK button 31 is alsoused for this function. Specifically, determination as to whether or notthe OK button 31 has been operated is carried out. If the result ofdetermination is that the update button is not on, then similarly to thefirst embodiment steps #155B and after are executed.

On the other hand, if the result of determination in step #154B is thatthe update button is on, there is a jump to step #127, and besidesreading out image data similarly to the cycle time elapsed time andgenerating added image data, in step #137 an updated added image isdisplayed, and the liquid crystal monitor backlight 26 a is lit up(#139).

In this way, with the seventh embodiment of the present invention, anupdate button is provided, and if this update button is operated, bypseudo creating a state that is the same as when the cycle time haselapsed, update of the added image is carried out, and the liquidcrystal monitor backlight 26 a is lit. Therefore, when the bulb exposureprogresses, it is possible to confirm the state of progress of the bulbexposure at an arbitrary timing other than the update timing of theimage.

Next, an eight embodiment of the present invention will be describedusing FIG. 30 and FIG. 31. With the first to seventh embodiments, thecycle time for the added image could not be changed during bulbexposure. With the eighth embodiment, it is made possible to change thiscycle time during an exposure operation for bulb exposure.

The structure of the eighth embodiment is the same as that of the fifthembodiment shown in FIG. 23 to FIG. 25, the flowcharts shown in FIG. 4,FIG. 6, and FIG. 18 are also the same, and bulb mode exposure timedisplay shown in FIG. 27, the exposure information display shown in FIG.10 and the update display shown in FIG. 11 are also the same. The pointof difference is that the flowchart showing the exposure operation shownin FIG. 26 is replaced with the flowcharts in FIG. 30 and FIG. 31, anddescription will center on this difference. Each of the steps within theflowcharts shown in FIG. 30 and FIG. 31 that are the same as the stepsin the flowchart shown in FIG. 26 have the same reference numeralsattached, and detailed description thereof is omitted.

If the flowchart for the exposure operation is entered, then similarlyto the fifth embodiment it is determined in step #125 whether or not thecycle time has elapsed. If the result of determination is that the cycletime has elapsed, then similarly to the fifth embodiment step #127 andafter are executed.

On the other hand, if the result of determination in #125 is that thecycle time has not elapsed, it is determined whether or not the 2Rswitch is off (#151). If the result of determination is that the 2Rswitch is off, then similarly to the fifth embodiment steps #161B andafter are executed. On the other hand, if the result of determination isthat the 2R switch is not off, it is then determined whether or not theinformation setting dial 24 has been operated (#181B).

If the result of determination in step #181B is that the informationsetting dial 24 has not been operated, then similarly to the fifthembodiment steps #155B and after are executed. On the other hand, if theinformation setting dial 24 has been operated, the subroutine for cycletime input described using FIG. 18 is executed (#183B). In thissubroutine for cycle time update, the operation state of the informationsetting dial 24 is determined, and it is possible to change the cycletime.

If cycle time input is completed, then exposure information display iscarried out (#185B) similarly to step #13 (FIG. 4). The cycle time thatwas changed in step #183B is displayed. Next, similarly to step #111B, amanually input cycle time is set (#187B). If setting of cycle time iscompleted, there is a jump to step #127, and following thatdetermination as to whether or not the cycle time has elapsed in step#125 is carried out based on the cycle time that has been changed inthis step.

In this way, with the eighth embodiment of the present invention, if theinformation setting dial 24 is operated during execution of bulbexposure, the cycle time is changed in accordance with the operationstate of the information setting dial 24, and after that the cycle timefor added images is changed based on the changed cycle time. Therefore,when the bulb exposure progresses, if the cycle time is shortened orlengthened it is possible to change the cycle time for images.

Also, as has been described, in the fifth to eighth embodiments of thepresent invention, the display screen of the rear surface liquid crystalmonitor 26 is illuminated for only a predetermined time in associationwith update of the image display on the rear surface liquid crystalmonitor 26. It is therefore possible to limit consumption of the powersupply battery as much as possible.

In the fifth to eighth embodiments, the rear surface liquid crystalmonitor 26, as the display section, is illuminated by the liquid crystalmonitor backlight 26 a, but as long as the display illumination sectionperforms illumination so that it is possible to easily confirm displayon the display section, it is not limited to a backlight. Theillumination section can be appropriately selected according to themembers used as the display section.

Also, in the fifth to eighth embodiments, in order to indicate the factthat bulb exposure has started, notification display for bulb exposurewas displayed at the time of commencing bulb exposure, it is alsopossible to continue display during execution of bulb exposure, and atthis time it is possible to display elapsed time after commencement ofbulb exposure. Also, the characters “bulb exposure” and “BULB” aredisplayed as the bulb exposure notification display, but this is notlimiting and it is also possible to have another display such as asymbol or an icon.

Next, a ninth embodiment of the present invention will be describedusing FIG. 32 to FIG. 35. In the first to eighth embodiments, update ofadded images was carried out at cycle time intervals. However, bulbexposure etc. extends over a comparatively long time, and there is novariation in a display image until the image is updated, which meansthat there is problem of looking at the display image for that entiretime.

Therefore, in the ninth embodiment, notification is given to thephotographer at the time of image update using a sound generatingsection or the like. In this way, it is possible for the photographer toobserve a display image without difficulty in a long time exposure suchas bulb exposure.

The structure of the ninth embodiment is partially similar to thestructure of the first and third embodiments, and so detaileddescription of parts of the structure that are the same will be omitted.

The external appearance of a digital single lens reflex camera of theninth embodiment of the present invention is the same as in FIG. 1.Electrical circuits of this digital single lens reflex camera are shownin FIG. 32. Compared to the electrical circuits of the first embodiment(refer to FIG. 2), the ninth embodiment differs only in that thetemperature measurement circuit 231 has been omitted, a buzzer 287 hasbeen added, and a liquid crystal monitor backlight 26 a has been added.

The omission of the temperature measurement circuit 231 is the same asin the third embodiment shown in FIG. 16. Also, the liquid crystalmonitor backlight 26 a is arranged on the rear surface of the liquidcrystal monitor 26, and illumination of the rear surface liquid crystalmonitor 26 is the same as for the fifth embodiment in FIG. 24.

Also, the buzzer 287 connected to the data bus 252 is a sound generatingsection described later, and performs notification display using soundwhen an image is updated at the time of bulb exposure. The structureother than for the points of difference described above is the same asfor the first embodiment shown in FIG. 2, and so detailed descriptionwill be omitted.

FIG. 33 shows a structure relating to image display during exposure, forbulb exposure. Compared to the first embodiment (refer to FIG. 3) thereis a difference in that the setting section 298 is omitted, and thesound generating section 299 a is provided. Naturally, the settingsection 298 can also be provided in the ninth embodiment, but as it isnot important it has been omitted in FIG. 33.

Also, in the ninth embodiment the sound generating section 299 aconnected to the control section 297 is provided, and this soundgenerating section 299 a is constituted by a buzzer 287. The soundgenerating section 299 a issues a notification to the photographer usinga notification sound every time the added image displayed on the imagedisplay section 296 is updated.

With this type of arrangement, display on the rear surface liquidcrystal monitor 26 at the time of bulb exposure is first displayingnotification information 321 a at the time of commencement of bulbexposure to notify that the bulb exposure has commenced (FIG. 35( a)).

If the initial cycle time has elapsed, image data is read from theimaging section 291, and an added image (at the initial stage, with theinitially read image data directly) is displayed on the rear surfaceliquid crystal monitor 26 as shown in FIG. 35( b) together with thenotification information 321 b (with this example, cycle time is 30seconds). Also, at the same time a sound (for example a beep) is outputfrom the sound generating section 299 a to notify of update of theimage.

After that, image data that has been acquired by the imaging section 291is sequentially added by the adding processing section 294 every setcycle time, and this added image is displayed on the image displaysection 296. As shown in FIG. 35( c) to FIG. 35( g), every time theadded image is updated, notification information 320 c to 320 g isdisplayed superimposed, and at the same time notification is alsocarried out using a notification sound from the sound generating section299 a.

Also, at the stage of FIG. 35( b) the exposure time is insufficient andso the image is dark, but after that if the images are gradually changedto brighter images and the cumulative adding is repeated a number oftimes, it will become an image that appears over exposed, as shown inFIG. 35( g). In addition to this notification information 321 b to 320 gbeing present during execution of bulb exposure, the elapsed time forthe bulb exposure is displayed.

Next, detailed operation of the digital single lens reflex camera of theninth embodiment of the present invention will be described using theflowchart shown in FIG. 34. In the ninth embodiment also, if a batteryis fitted, the processing flow for power on reset is executed. Theprocessing flow for this power on reset is the same as in FIG. 4 for thefirst embodiment, and so detailed description will be omitted.

Also, cycle time input of step #31 in the processing flow of the poweron reset (refer to FIG. 4) is the same as the processing flow of thecycle time input in the third embodiment (refer to FIG. 18) and sodetailed description is omitted. Also, the shooting operation of step#37 in the processing flow of the power on reset (refer to FIG. 4) isthe same as the processing flow of the shooting operation in the firstembodiment (refer to FIG. 6) and so detailed description is omitted.

Next, the exposure operation of step #75 within the shooting operationprocessing flow (FIG. 6) will be described using FIG. 34. In thedescription, steps carrying out the same processing as the flow of FIG.7 for the first embodiment have the same step numbers attached, anddetailed description thereof is omitted.

If this processing flow is entered, first, similarly to step #9 (referto FIG. 4), it is determined whether or not bulb mode has been set(#101). If the result of determination is that bulb mode has not beenset, normal exposure mode, such as program exposure mode, is executed instep #103 to step #115. This normal exposure mode processing is the sameas for the flow of FIG. 7, and so detailed description is omitted.

If the result of determination in step #101 is that bulb mode has beenset, then first the added image storage region that has been allocatedinside the temporary storage section 293 is cleared (#119C), and thecycle time that was manually input in step #31 is set (#120C). Next, atimer for display cycle time timing is started (#121C), and similarly tostep #105, together with opening of the shutter 213 imaging is commenced(#122C).

Display of notification information 321 a for bulb exposure, such as isshown in FIG. 35( a) is then started (#123C). That is, at the time bulbexposure commences, the screen is jet black, and if there is no displayat all the photographer will be unsure as to whether or not the exposureusing bulb exposure has started. In this embodiment also therefore,similarly to the third embodiment, by displaying the notificationinformation 321 a it is possible for the photographer to recognize thatthe exposure has started.

If the display of notification information is started, then next theliquid crystal monitor backlight 26 a is lit up (#124C), to illuminatethe rear surface liquid crystal monitor 26. In this way, the displayscreen of the liquid crystal monitor 26 becomes bright and it ispossible to view.

Next, it is determined whether or not the timer for cycle time timinghas reached the cycle time set in step #120C (#125). If the result ofdetermination is that the cycle time has not elapsed, it is determinedwhether or not the full pressing of the release button 21 has beenreleased, that is, whether or not the 2R switch is off (#151).

If the result of determination in #151 is that the 2R switch is not off,it is next determined whether or not the image display is maintainedover a predetermined time (#161C). In this step, it is determinedwhether or not the timer for cycle time timing that started a timingoperation in step #121C (or in step #131C the second and subsequenttimes) has reached a predetermined time, for example, 10 seconds.

If the result of determination in step #161C is that the predeterminedtime has not been reached, step #125 is returned to and image display bythe liquid crystal monitor 26 and lighting of the liquid crystal monitorbacklight 26 a are continued.

On the other hand, if the result of determination in step #161C is thatthe predetermined time has elapsed the liquid crystal monitor backlight26 a is turned off (#163C) and display of the added image on the liquidcrystal monitor 26 is turned off (#165C). This is in order to reducepower supply consumption, so that the added image is displayed for onlya predetermined time at the time of update.

With this embodiment, notification display for the bulb exposure isdisplayed on the liquid crystal monitor 26, but by also turningnotification display for bulb exposure in addition to turning off theimage display of step #165C, and turning off the power supply to theliquid crystal monitor 26 itself, it is possible to further reduce powersupply consumption. In step #165C, if the image display is turned off,step #125 is returned to.

If the result of determination in step #125 is that the cycle time haselapsed, then similarly to step #109 and step #111, image forming of theimage sensor 221 is stopped with the shutter 213 still open, and readingof pixel signals is carried out (#127, #129).

Next 1 is added to the counter (#130C). The update counter is reset atthe same time as the timer is started in step #121, and every time thisstep #130 is passed through 1 is added. By multiplying a count value ofthis update counter by the cycle time set in step #120, it is possibleto obtain a cumulative time from when the exposure using bulb exposurestarted.

Next, the timer for cycle time timing is restarted (#131C), and imagingon the image sensor 221 is commenced (#133C).

Next added image data is read from a storage region that was previouslystored in the storage region of the temporary storage section 293, andadding processing for this image data and image data read in step #129is carried out (#135C). Image data of the added image obtained here isstored in a storage region of the temporary storage section 293 that isused for added image storage (#137C).

If accumulation of the added image is completed, the added image storedin the temporary storage section 293 is next displayed on the rearsurface liquid crystal monitor 26 (#139). Illumination of the liquidcrystal monitor 26 is then carried out using the liquid crystal monitorbacklight 26 a. As has been described, with image display using theliquid crystal monitor 26 and illumination using the liquid crystalmonitor backlight 26 a, display of an added image is turned off if addedimage display continues for a predetermined time (#163C, #165C).

Next, it is determined whether or not the cycle time set in step #120Cis 30 seconds or more (#143C). If the result of determination is thatthe set cycle time is 30 seconds or more, a notification sound isemitted for a predetermined time (for example 0.3 seconds) by the soundgenerating section 299 a (buzzer 287). It is possible to let thephotographer know that the image has been updated using the notificationsound.

Here, the fact that whether or not to emit a notification sound isswitched depending on whether or not the set cycle time is a determinedtime or longer is because in the event that the cycle time is short,intervals between emission of the notification sound will be short,giving a noisy impression. This determined time is not limited to 30seconds, and can be appropriately altered. If the result ofdetermination in step #143C is that the set cycle time is less than 30seconds, or if the notification sound has been emitted in step #145C,step #125 is returned to and the previously described operations areexecuted.

In step #122C, at the initial stage where the imaging operation hascommenced notification information 321 a is displayed on the liquidcrystal monitor 26, as shown in FIG. 35( a), and illuminated by theliquid crystal monitor backlight 26 a. If it is determined in step 161Cthat the predetermined time has elapsed, illumination by the liquidcrystal monitor backlight 26 a is turned off.

Next, if it is determined in step #125 that the cycle time has elapsed aformed image is read out, and the image at this time is displayed asshown in FIG. 35( b) (#139C), and at the same time if the set time is 30seconds or greater a notification sound is emitted by the soundgenerating section 299 a (#145C). Also, illumination by the liquidcrystal monitor backlight 26 a is carried out for a predetermined time(from #141C to #163C).

As shown in FIG. 35( c) to FIG. 35( g), every time it is determined instep #125 that the cycle time has elapsed, the added image andnotification display 320 c to 320 g are updated. At this time anotification sound is also emitted for a predetermined time. At theinitial stage the added image is insufficiently bright, and so thescreen remains dark, but with the screen becoming brighter as theaccumulation time increases the photographer completes the bulb exposureat the point in time when they determine that their desired brightnesshas been attained.

As the notification information 321 b to 320 g, as shown in FIG. 35there is display indicating that bulb exposure is being executed, anddisplay of cumulative exposure time for the bulb exposure. Also in thisembodiment, the cumulative exposure time is obtained using a count valueof the update counter that is made to count in step #130C and the setcycle time, but this is not limiting and it is also possible to providea counter for obtaining the cumulative exposure time at the time of bulbexposure, and displaying elapsed time based on this counter.

If it is determined in step #151 that the 2R switch has been turned offas a result of the photographer taking their finger off the releasebutton 21 at the point in time where their desired brightness has beenreached, then similarly to step #127 imaging is stopped together withclosing of the shutter 213 (#153). Specifically, the exposure operationis completed, and after that the original routine is returned to.

In this way, with the ninth embodiment of the present invention, everytime the set cycle time elapses (Y at #125), imaging by the image sensor221 is stopped, image data is output, this image data and an immediatelypreceding added image stored in the storage region of the temporarystorage section 293 are added, and the result is stored. The added imagestored in each storage region is updated and displayed in the rearsurface liquid crystal monitor 26 every time the cycle time elapses, asshown in FIG. 35.

Also, with this embodiment, every time the image is updated anotification sound is emitted by the sound generating section 299 a, andwhen this notification sound is emitted, since the rear surface liquidcrystal monitor 26 should only be viewed when the notification sound isemitted, the photographer can view without any problem.

Further, with this embodiment, after the image has been updated theliquid crystal monitor backlight 26 a is only lit for a predeterminedtime, which means that it is possible to reduce consumption of the powersupply. Also, since the notification sound by the sound generatingsection 298 is stopped if the set cycle time is short, it is possible toprevent the notification sound being emitted at short time intervals.

In this embodiment, as notification information there are displayindicating bulb exposure and display of the elapsed time from the startof bulb exposure, but it is also possible to omit the elapsed time.Also, the characters “bulb exposure” and “BULB” are displayed in orderto indicate that bulb exposure has commenced, but this is not limitingand it is also possible to have another display such as a symbol or anicon.

Next, a tenth embodiment of the present invention will be describedusing FIG. 36 to FIG. 40. In the first to ninth embodiments, addedimages were displayed over the course of a long time exposure, such asbulb exposure. However, when confirming the image after exposure, therewill be times when it is instantly recognized that exposure is wrong.

In the tenth embodiment therefore, individual added images acquired overthe course of a long time exposure such as bulb exposure are stored, sothat it is possible to confirm the individual added images afterexposure.

The structure of the tenth embodiment is partially similar to thestructure of the first and third embodiments, and so detaileddescription of parts of the structure that are the same will be omitted.

The external appearance of the digital single lens reflex camera of thetenth embodiment is similar to FIG. 1, and electrical circuits aresimilar to FIG. 16, and so detailed description will be omitted.

Next, the structure relating to image display during exposure, in bulbexposure etc., will be described using FIG. 36. Similarly to FIG. 3, thecontrol section 297 is constructed of a body CPU 251 for controlling theoverall digital single lens reflex camera.

The imaging section 291, similarly to FIG. 3, includes the image sensor221 image sensor drive circuit 223, ADC circuit 225 and dark currentelimination circuit 227, and outputs image data based on image signals.Output of the imaging section 291 is connected to the adding processingsection 294.

The adding processing section 294 is made up of the body CPU 251 and animage processing circuit 257. The adding processing section 294 is inputwith image data from the imaging section 291, and also input withprevious added image data stored in the storage region of the addedimage storage section 292, and adds the two together to generate anadded image and outputs the result to the added image storage section292.

The added image storage section is constituted by a temporary storagedevice such as SDRAM 267, and has a plurality of storage regions dividedinto from storage region A to storage region n, with each storage regionsequentially storing the added image data thus far.

That is, initial image data is stored in the storage region A, then ifimage data is output from the imaging section 291, adding processing forthat image data and previous added image data stored in the storageregion A are carried out, and new added image data is stored in thestorage region B. In this manner, in accordance with control by thecontrol section 297, every time image data is output from the imagingsection 291, image data to that point is subjected to adding processingand sequentially stored in the storage regions in the added imagestorage section 292.

The image display section 296, similarly to FIG. 3, is comprised of aliquid crystal monitor 26 and a liquid crystal monitor drive circuit263, and displays image data that has been read from the added imagestorage section 292.

A selection section 298 a is made up of a cross-shaped button 20 and anOK button 31, and selects a finally stored image from among a pluralityof subject images formed at the time of bulb exposure. The image storagesection 295, similarly to FIG. 3, is comprised of a storage medium 277,and stores an image selected by the selection section 298 a.

With this type of structure, the control section 297 causes output ofimage data from the imaging section 291 at intervals of the set cycletime, and the adding processing section 294 adds this image data to thepreceding added image stored in the added image storage section 292.Added values for image data up to the time of respective image dataoutput are then stored in a respective storage region of the added imagestorage section 292.

An image based on the image data stored in the added image storagesection 292 is then displayed on the image display section 296. Imagedata stored in storage region A has the earliest exposure, and so is anmage that appears under exposed, as shown in FIG. 39( a). Next, sincethe next stored image of storage region B is added to the image datahaving the initial exposure, it becomes slightly brighter as shown inFIG. 39( b).

Every time image data is sequentially accumulated in the added imagestorage region 292, the image becomes gradually brighter, with the imageof the storage region D approaching correct exposure, as shown in FIG.39( d), and if accumulation of image data continues further it becomesan over exposed mage as shown in FIG. 39( g) that is stored in storageregion G.

If exposure is completed, images based on image data stored in therespective storage regions are displayed in tabulated form asthumbnails, as shown in FIG. 40, on the image display section 296. Inthe case immediately after completion of bulb exposure, a selectionframe 341 indicates an image corresponding to the final exposure.

The photographer selects an image that accords with their intentionsfrom among the images shown in table form by moving the selection frame341 by operating the cross-shaped button 30 until it indicates a goodimage, and then using the OK button 31. If the image is selected, thatimage is stored in the storage medium 277.

Next, detailed operation of the digital single lens reflex camera of thetenth embodiment of the present invention will be described using theflowchart shown in FIG. 37. In the tenth embodiment also, if a batteryis fitted, the processing flow for power on reset is executed. Theprocessing flow for this power on reset is the same as in FIG. 4 for thefirst embodiment, and so detailed description will be omitted.

Also, cycle time input of step #31 in the processing flow of the poweron reset (refer to FIG. 4) is the same as the processing flow of thecycle time input in the third embodiment (refer to FIG. 18) and sodetailed description is omitted.

The shooting operation of step #37 in the processing flow of the poweron reset (refer to FIG. 4) will be described using the flowchart shownin FIG. 37. Processing flow of this shooting operation is the same asthe processing flow of the shooting operation in the first embodimentshown in FIG. 6, and steps #61 to #79, step #83 and step #85 Stepscarrying out the same processing therefore have the same step numbersattached, and description will center on pints of difference.

If the 1R switch is turned on, processing flow for the shootingoperation is entered, processing advances to step #61 to step #69, andif the 2R switch is turned on there is a transfer to operation forcarrying out exposure in step #71 and after.

The exposure operation is started in step #75. In this step, travel ofthe front curtain of the shutter 213 commences, together with chargeaccumulation of the image sensor 221. Then, if a time corresponding tothe shutter speed acquired in step #67 or a shutter speed that wasmanually set by the photographer has elapsed, travel of the rear curtainof the shutter 213 starts, and charge accumulation of the image sensor221 is terminated.

Here, if bulb mode has been set, then while the release button 21 isbeing pressed down completely the shutter 213 is open, and at this timeimage data is repeatedly acquired using the image sensor 221 atintervals of the cycle time, and an added image is displayed on theliquid crystal monitor 26 while being updated, based on this image data.This exposure operation will be described in detail later using FIG. 38.

If the exposure operation is completed, an instruction to open up theaperture 103 is output to the CPU 111, the aperture 103 is opened up(#77), and an operation to restore the movable mirror 201 to the loweredposition is carried out (#79). Then, as in step #65, it is determinedwhether or not there is bulb mode (#81D).

If the determination in step #81D is that it is not bulb mode, imageprocessing of data for a normal image read from the image sensor 221 andtemporarily stored in the SDRAM 267, or for an added image, is carriedout, and the image processed image data is stored in the storage medium277 (#83). Display of the image that is displayed on the rear surfaceliquid crystal monitor 26 is the stopped (#85). Once image display isstopped, the original routine is returned to.

If the result of determination in step #81D is that there is bulb mode,all added images are displayed as a list (#89D). That is, thumbnaildisplay is carried out as shown in FIG. 39A based on image data storedin respective regions of the added image storage section 292. The newestimage, that is the finally exposed image, is then selected, and displayof the selection frame 341 is carried out (#91D).

Next, determination as to whether or not the cross-shaped button 30 hasbeen operated is carried out (#93D), and if it has not been operatedthere is a jump to step #97D. On the other hand, if the result ofdetermination is that the cross-shaped key 30 has been operated theselection frame 341 is moved in accordance with the operation directionand the selected image is changed (#95D).

It is then determined whether or not the OK button 31 is operated(#97D), and if the result of determination is that the OK button 31 hasnot been operated step #93 is returned to and the previously describedprocessing is executed. On the other hand, if the result ofdetermination is that the OK button 31 has been operated then image dataof the selected image is read out from the added image storage section292 (#99D). If reading is complete, processing advances to previouslydescribed step #83, and processing is executed.

Next, the exposure operation of step #75 within the shooting operationprocessing flow of FIG. 37 will be described using FIG. 38. In thedescription, steps carrying out the same processing as the flow of FIG.7 for the first embodiment have the same step numbers attached, anddetailed description thereof is omitted.

If this processing flow is entered, first, similarly to step #9, it isdetermined whether or not bulb mode has been set (#101). If the resultof determination is that bulb mode has not been set, normal exposuremode, such as program exposure mode, is executed in step #103 to step#115. This normal exposure mode processing is the same as for the flowof FIG. 7, and so detailed description is omitted.

If the result of determination in step #101 is that bulb mode has beenset, then first the entire added image storage region that has beenallocated inside the added image storage section 293 is cleared (#119D),and the cycle time that was manually input in step #31 is set (#120D).

Next, a timer for display cycle time timing is started (#121), andsimilarly to step #105, together with opening of the shutter 213 imagingis commenced (#123). Next, it is determined whether or not the timer forcycle time timing has reached the cycle time set in step #120D (#125).

If the result of determination is that the cycle time has not elapsed,it is determined whether or not the full pressing of the release button21 has been released, that is, whether or not the 2R switch is off(#151). In the event that the 2R switch is on and the cycle time has notelapsed, a standby state is entered where the determinations at steps#125 and #151 are alternately executed.

If the result of determination in step #125 is that the cycle time haselapsed, then similarly to step #109 and step #111, image forming of theimage sensor 221 is stopped with the shutter 213 still open, and readingof pixel signals is carried out (#127, #129). Next, the timer for cycletime timing is restarted (#131D), and imaging on the image sensor 221 iscommenced (#133D).

Next added image data is read from a storage region that was previouslystored in the storage region of the added image storage section 293, andadding processing for this image data and image data read in step #129is carried out (#135D). Image data for the added image acquired here isstored in a storage region adjacent to the storage region previouslyread by the added image storage section 293 (#137D). This stored addedimage is then displayed on the rear surface liquid crystal monitor 26(#139D), step #125 is returned to, and the previously described stepsare executed.

If the result of determination in step #151 is that the full pressing ofthe release button 21 has been released, that is, it has been determinedthat the 2R switch has been turned off, then imaging is stopped togetherwith closing of the shutter 213 (#153). Specifically, the exposureoperation is completed, and after that the original routine is returnedto.

In this way, every time the cycle time set in step #31 (#120D) elapses(Y at #125), imaging by the image sensor 221 is stopped, image data isoutput, added images of this image data and an immediately precedingadded image stored in the storage region of the added image storagesection 292 are obtained, and sequentially stored. The added imagestored in each storage region is updated and displayed in the rearsurface liquid crystal monitor 26 every time the cycle time elapses, asshown in FIG. 39. At the point in time when the cycle time initiallyelapses, since cycle time is short a completely dark image results, andthe image is gradually made brighter by cumulatively adding image dataeach time the cycle time elapses.

With the tenth embodiment, if bulb mode has been set an exposureoperation is repeated during the bulb exposure operation at cycle timeintervals, image data acquired at this time and a previous added imageare added, this added data is respectively independently stored in theadded image storage section 292, and after completion of exposure it ispossible to select from a plurality of added images. It is thereforepossible to acquire an image of an appropriate exposure level afterexposure.

Also, with this embodiment added images are displayed as a list on theliquid crystal monitor 26. It is therefore possible to compare theindividual added images and easily select the image the photographerdesires. Further, with this embodiment a period for acquiring repeatedoutput from the imaging section 291 (cycle time) is variable, and so itis possible to make it an optimum period according to characteristics ofthe subject image.

Further, with this embodiment added images during exposure are displayedin accordance with progress of the exposure, which is useful, with bulbexposure, in determining the time at which to complete exposure.

With this embodiment added images are displayed in order to showexposure level during exposure, but if it is simply used to finallyselect an image it is possible to omit the display of added imagesduring exposure.

Further, with this embodiment reading out of a selected image is carriedout in step #97 and step #99, but the selected image is not limited toone and it is also possible to read out a plurality of added images.

As has been described above, with each of the embodiments of the presentinvention, image data that has been repeatedly read from an imagingsection 291 is sequentially added, and added image data is generated anddisplayed on the image display section 296. It is therefore possible toconfirm the advancement of exposure at the time of a long time exposuresuch as bulb exposure. It is also possible to display added images thathave been stored in an added image storage section in the form of a listafter a long time exposure such as bulb mode. It is therefore possibleto select an image that conforms to the intended exposure by thephotographer after exposure.

With each of the embodiments of the present invention, if the bulb modehas been set, the release button 21 is pressed down fully, and untilthis full pressing down is released, that is, while the 2R switch is on,the shutter is opened and the exposure operation carried out. However,as well as this method of operating, it is also possible, for example,to start the exposure operation when the release button 21 is presseddown fully (first release operation), continue the exposure operationeven if the full pressing of the release button 21 is released, and stopthe exposure operation when the release button 21 is pressed down fullyagain (a second release operation carried out after the first releaseoperation).

Also, in the first, second and fifth to eighth embodiments, if theexposure operation is completed, an image is read out in steps #155(FIG. 7, FIG. 14) and step #163B (FIG. 26, FIG. 28 to FIG. 30), and anadded image that has been added to this image is displayed (#161,#169B). However, it is also possible to not read an image in step #155or step #163B, but display the final added image acquired in step #137.

Further, in each of the third, fourth, ninth and tenth embodiments ofthe present invention, when the exposure is completed, if imaging isstopped in step #153 (FIG. 19, FIG. 21, FIG. 34, FIG. 38) there is noreading of image signals from the image sensor 221. However, similarlyto the first, second and fifth to eighth embodiments, it is totallypossible to read an image after stopping imaging, perform addition, anddisplay the added image.

Further, with the second embodiment of the present invention, an exampleis shown where added images are generated even if a long time exposureis carried out, but in other embodiments also it is also possible togenerate and display added images in the case where long time exposureis carried out, for example, exposure of a few seconds.

Further, in the first and third to eighth embodiments, the cycle time ismanually set in step #31. However, this is not limiting and it is alsocompletely possible, similarly to the second embodiment, toautomatically set the cycle time according to subject brightness, so asto either shorten the cycle time if the brightness is high, orconversely to extend the cycle time if the brightness is low.

Also, this embodiment has been described as an example applied to asingle lens reflex type of digital camera, but besides being applied toa single lens reflex camera there is no problem with the presentinvention being applied to a compact type digital camera or a camera ofthe type incorporated into a mobile telephone or PDA (mobile informationterminal: Personal Digital Assistant) etc. As long as it is has animaging device capable of long time exposures, such as bulb mode, it ispossible to apply the present invention.

Description has been given above embodiments of the present invention,but the present invention is not limited to these embodiments, andstructural elements may be modified in actual implementation within thescope of the gist of the embodiments. It is also possible form variousinventions by suitably combining the plurality structural elementsdisclosed in the above described embodiments. For example, it ispossible to omit some of the structural elements shown in theembodiments. It is also possible to suitably combine structural elementsfrom different embodiments.

1. An imaging device, comprising: an imaging section for repeatedlyforming subject images in a set period while bulb exposure is beingperformed, and outputting image data; an adding processing section forcarrying out addition processing with previous image data each time theimage data is output, to generate an added image; an image displaysection for displaying the added image; and a designation section fordisplaying notification information indicating that bulb exposure isbeing performed, on the image display section, for a specified periodfrom commencement of the bulb exposure, instead of the added image. 2.The imaging device of claim 1, wherein: the specified period is a perioduntil a brightness level of the added image reaches a predeterminedlevel.
 3. The imaging device of claim 1, wherein: the specified periodis a period until an elapsed time from commencement of the bulb exposurereaches a predetermined value.
 4. The imaging device of claim 1,wherein: after elapse of the specified period, the added image isdisplayed, and at the same time notification information indicating thatthe bulb exposure is being executed is displayed superimposed on part ofthe added image.
 5. The imaging device of claim 1, wherein: thenotification information is further display of elapsed time fromcommencement of the bulb exposure.
 6. A control method for an imagingdevice, comprising: after commencement of designation of bulb exposure,repeatedly forming subject images in a set period and acquiring imagedata; adding to a previous image every time the image data is output,and displaying an added image; and in a specified period fromcommencement of the bulb exposure, displaying notification informationindicating that bulb exposure is in progress, instead of the addedimage.
 7. An imaging device, comprising: an imaging section forrepeatedly forming subject images in a set period while bulb exposure isbeing performed, and outputting image data; an adding processing sectionfor carrying out addition processing with previous image data each timethe image data is output, to generate an added image; an image displaysection for displaying the added image; and a designation section fordesignating so as to display only notification information indicatingthat bulb exposure is being performed, on the image display section, fora given period from commencement of the bulb exposure.
 8. The imagingdevice of claim 7, wherein: the given period is a period fromcommencement of bulb exposure until display of an initial added image.